I think the important thing is that people know these questions should be asked eventually, but I agree it can be later.

Too many people are giving the advise "it doesn't matter" but for all the reasons you mentioned I think it does matter a lot. You should consider your first account a throw-away while you start to understand Lemmy and what a home instance means to you, then be ready to ditch it and start fresh (until account porting is implemented).