To invest, a person needs basic knowledge about Bitcoin, faith in Bitcoin, and a source of discretionary income. If a person has these things, then he should invest immediately.
I agree with you on two out of the three requirements you listed here. The one I disagree with is faith in bitcoin, because someone don't need faith in bitcoin to invest in it, because with or without faith bitcoin will do what it intends to do. It is not ones faith that makes bitcoin what it is. Bitcoin reacts to the law on of demands and supply and not faith. Faith is something that's more related to religious fantasies and bitcoin is not a religious something. Bitcoin is not related to any religious beliefs. That being said, an investor doesn't need faith to invest in bitcoin.