It's complicated. My sentiment toward my old self is that he is dead. Shouldn't have existed in the first place and only came to be because a little kid was too afraid to speak up.

I can understand why someone I knew before I transitioned would be disappointed. But I don't care and if they express that feeling towards me, then yes I am offended. My life has nothing to do with you and I don't owe you any say in it. Because you obviously don't know me well enough that you should. That beeing said I don't think that I have changed that much. Or at least not more than cis people change over the years. Keep in mind that that my perspective on my transition.

In general I think it's okay to feel what you feel. But before you express those feelings to someone you might want to ask yourself if you're actually close enough to the person who wants to transition to have any say in it.