I've attended one wedding for a young couple that was two years older than me. A year later, they were expecting a child. Where was I during that time in my life? Still in college, working part-time while going to school full-time, barely able to maintain and support my own relationship.
By the time my own mother was 23, she was married to my father. At 27, she had her first child, my sister. Myself, at the age of 21, has just learned how to make a grilled cheese sandwich the right way. But I asked my mom if I was falling behind because others my age were engaged and buying their own houses, and she said that everyone was going at their own pace and doing things their own way.
Just because you see other people "thriving" and "living their best life" doesn't mean you're not succeeding as well. Maybe your college degree is taking longer to achieve because you've chosen to double major or apply to grad school. Maybe your romantic relationships aren't leading to a marriage proposal because you haven't found the right person yet. Don't rush! You have a lot of life to live and there's no reason to hurry through it.
You don't have to compare your successes to others, so long as you're succeeding in your own way. You should be proud of every achievement and every milestone you make because the little things are just as important as the big ones.
There's no reason to feel like you need to have life figured out right now. While others may be getting their dream jobs and taking solo trips around the globe, you may be taking your time to figure your own stuff out before jumping headfirst into uncertainty.
Take your time! Breathe! Plan it out! But never let yourself feel like you're falling behind because everyone else may seem far ahead.