21st birthdays are typically full of the three Bs: beer, Bailey's, and Bacardi. By the time you hit that 21st year, however, you should have some admirable life lessons under your belt.

Take time to yourself.

Self-care is one of the most important things in the world. It'll give you the energy to tackle the world and it will give you time to get to know yourself. After all, the first step to loving yourself is taking time to treat yourself.

Just say yes.

If you're tentative about going on the date, just go-- maybe it will turn into true love. If you're nervous about traveling to a new place, just got for it. If you don't know if you should try the new sushi burrito, you should. Opportunities don't always come around and no grand changes are made in the boundaries of your comfort zone.

Always make time for your family.

Yes, this is a period of time full of change. You're finishing up school, maybe pursuing more. You're thinking about getting married, maybe having some kids or adopting an animal. No matter what, you need to make time for those who were there for you during the whole journey -- your family.

It's okay to change your mind.

Whether you're thinking about changing your major or considering cutting off a friendship, it's okay. This is the time of your life to be selfish and to do what's best for you.

Eat the extra slice of cake.

Why are you wasting time by counting calories? In 50 years, I bet you're more likely to remember that delicious cake you ate, not the time spent counting each calorie in each and every meal to prep for the summer.

Pick your battles carefully.

Sometimes, it's not worth it to fight about every little itty bitty thing. Think about what will matter in the long run. If it won't matter in 10 years, let alone 10 days, then it is not worth the effort.

Know when to apologize.

It's nice to think that you're never to blame, but that's not the reality. It's important to acknowledge when you did something wrong and to properly apologize for it. It'll make you feel relieved and all parties involved feel a little better.

Something that you can't apologize for are your feelings.

You cannot apologize for the way you feel; you simply can't. It's a fact. If you're in love, say it. If you're unhappy in a given situation, say it. Life is much too short to lie about and hide what you're truly feeling.

Always stop to pet a puppy.

This may not be a universal rule, but it's definitely a rule in my book. If you see a peppy puppy walking around, stop and give him or her a belly rub (with the owner's permission, of course). Your mood will instantly increase, I guarantee it.

Breathe.

Take a minute, stop, and just breathe. Whatever is happening, it's going to work out the way it's supposed to. Life can be overwhelming. Just don't forget to breathe.

The world doesn't owe you anything.

Not your parents, not your teachers, not your coworkers, not your friends -- no one. If you want anything in life, you're going to need to work hard for it. Things worth having do not come easy.

Put down your phone.

Yes, Facebook and Instagram and Snapchat and Twitter are all full of the hottest and most interesting gossip. But, you know what? Nothing can replace real human interaction. If you're with someone, give them your full and undivided attention. You don't know how long people will be around for.

You don't need to pretend to be the person who everyone thinks you are.

Maybe everyone sees you as the shy, smart, pretty girl. It's nice to have people think good things about you, right? Well, sometimes it's all a facade and we don't really live into people's expectations, and that's okay. Be who you truly are. Those who love you will stand by you.

Wash your clothes once a week.

You may have enough clothes to get you through more than one week, but just get yourself into a habit. Future you will thank you for this proper example of time management.

The grass isn't always greener.

The new job may indeed be worth it, but it also may be a total bust. You may envy another person's friendship, but under the surface, it may be totally toxic. You should definitely take chances, but you can't take everything for face value; always dig a little deeper.

Send out some snail mail.

It may seem a bit old-fashioned, but hand written letters mean more than any text message could. The effort behind a letter is beautiful and it's something that can be saved forever. Take the extra time to show that you care.

Don't judge yourself based on others.

There are always going to be people who you think are more successful than you, more beautiful than you, more creative than you, or more personable than you. Everyone is facing their own battle that you know nothing about. Each individual has their own set of unique strengths and challenges. Nothing is uniform.

Travel.

Whether it's to another city, another state, or another country, just do it. There's never going to be a better time in your life to just pick up and go for a week or two. Now is the time to see new things and take a part in different experiences. Immerse yourself in other cultures.

The world isn't black and white.

It's not always this or that; it's not always tit for tat. There is not always a right or a wrong — there simply is. Look deeper into the meanings of things. Going through life with blinders on is only going to leave you unhappy. If you're unhappy with the options available, then make your own.

Don't let anyone steal your confidence.

You don't need anyone to believe in you but yourself. If someone doesn't have faith in you, that's their loss. If somebody doesn't see your potential, then take that potential elsewhere. Your talents are yours and yours only. Above all, it's important to believe in yourself.

You don't need 1,000 friends.

When it comes to friends, it's about the quality, not of the quantity. In high school and college, you're going to meet a lot of people. Some you may even consider to be your best friends. Well, through time and distance, you'll see which friendships are really worth keeping. You'll see the people who you want to have by your side forever and who will always be there for you.