I remember reading somewhere that an otaku can start with a free armor complex form equal in rating to his willpower. However, upon going back and looking at Matrix I can't find that anywhere. Does anyone know where this is writen, or am I just making stuff up again?

I've never read that.

I think youre just making stuff up.

As part of their living persona, Otaku get hardening at willpower/2, and bod at willpower. They also get programming * 50 Mp (so usually 300-350 Mp) worth of free complex forms, which could be used to buy a rating (whatever) armor.

That was in older editions, Otaku. The 3rd Edition rules do not have that rule anymore.