This is so me, well was...
you know from my experiences interest really depends on the first luck thingy, I mean if we get appreciated in something for the first time we do it, we get interested and eventually think wow this is something for me, on the other hand if we fail, we are like maybe this isn't something for me, I'm not interested and what can I do?
My failure is supposed to happen because I'm not interested!


Now now pretty much everything in world is interesting to someone...
How?
Because they feel this is the thing for them!
Why do they feel that?
Believe it or not somebody had told them or appreciated them most of the time...
I'm good at Mathematics.
Why?
I believe that!
I stick to my believe!
Truth is sometimes theorems revolve in my head for days and I still don't get it but after sometime I've seen I develop understanding eventually or just have practiced to the point I wouldn't need to know the "real meaning" I was searching in start, gradually I even find why I learned what I learned...
Math is simply unrelatable to real word but after sometime you get hang of things. Point I'm trying to make is, it takes practice and practice to understand something and interest eventually develop when you understand something, like wow this is so cool!
And when you practice, you become expert, good enough to be admired and praised (we all low-key need that)
and when that happens, you think this is so for me.
I hope I didn't preach much but just thought to share an experience because I was once you but not anymore :)
Goodluck