I don't know if one's sexuality "changes" per se -- but one may realize things about themselves they didn't before, due to denial, etc. or they may have a fluid sexuality where they experience differing attractions over time.
Change? no. You can't really change your physical attraction. Developed? Probably as you experience more of life and you realize you are more of this type of person than other, etc.
^This. Also my priorities have changed. I used to prioritize conformity, and a stable life; now I prioritize honesty and treating others well. What I want as a result has changed as well. But I think what you're asking is if it's possible for sexual identity to shift; absolutely. Ive gone from totally straight -> mostly gay in my identity; but the underlying orientation has not changed.
Tbh I think it's possible for people who're more fluid. For me personally I used to be kind of bisexual, but more attracted to girls and over the years my attraction to men has all but disappeared, which is why I now identify as a lesbian. Then again once in a blue moon I'll see a man and think " Damn he's hot" but that's about it. But yeah I think it can change, especially with fluid bi or pan people, one could easily go from kinsey 2 to 5 and back again for all it's worth. Then again the question is whether those people are just always bi or pan, because then label-wise nothing has changed, even though who they're attracted to might have changed a lot.