Friend,
It seems like everyone has their "thing." You know, that one thing that you're really good at. The thing that your friends mention when they are describing you to others. Everyone is good at something; however, these good qualities might be broader than we often acknowledge.
"She's an amazing singer." "He's phenomenal at drawing." "She can play every sport incredibly!" These are the most basic remarks on talent, but they are also some of the most common. Although activities like sports, theatre, school, visual art, and music all require huge amounts of talent, it is shallow of society to limit talent to those areas. Then why does it happen so often?
You're a teenager, college student, or young adult and you haven't found what you are good at? Don't forget people like J.K. Rowling, Vera Wang, and Leonard Cohen who didn't find success until after their thirties! Maybe it's going to take some exploring you haven't done yet to find your talent, or maybe you just haven't stepped out of your comfort zone enough yet!
Consider this: What were people like Mother Teresa and Ghandi known for? They aren't known for being amazing writers, or actors, or ball-players. They are known for being kind and peaceful people. Maybe your niche isn't a physical talent but an intellectual quality. Maybe you'll never be known for being the next great artist after Picasso, but you might be known for being a great dad! Physical talent and personal characteristics are equally important.
There is no reason to force yourself into hobbies which don't interest you just so you'll be known for something. Your "thing" will reveal itself in due time. Don't be afraid to take unconventional approaches to thoughts about talent. If you're an amazing cook, a hospitable host, or a master mechanic, you are gifted. The willingness to work in the medical field and care for people is a facility many don't have.
Competency and self-worth are not things that can be compared to others. Finding what you're good at later than others does not mean you're a late bloomer. Everyone does not mature at the same rate; neither do they develop who they are at the same rate. You are not worth less than others just because you don't know what you're "good at" yet. You may never truly know where you're niche is, but the people who remember you will. They will remember you as patient, or loving, or loyal. You will leave an impact in other people's lives no matter what. Do not consider yourself to others, no matter what. You are not a late bloomer, and you never will be. You are not talentless, and you never will be. You are not less appreciated. You are just as special and important as anyone else. Do not be discouraged by you not knowing what your niche is; your niche does not define you. It does not make you who you are.