I can't even keep my leg straight if I lift it halfway up, has anyone had success with being as inflexible as me and becoming a lot more flexible?

I've always been very inflexible, sometimes I do stretches and not too long ago I thought I was getting results.. (As in becoming MORE flexible) but I wasn't consistent.

I am 20, so maybe it IS possible for me to improve.. I know anyone can but I sometimes feel too old.

If so, what exercises helped you most in improving your flexibility? And how long did it take? Thanks!

Posted here because I am interested in ballet.