How should a new player determine when he's ready to move from one game type or format to another?

I have read these sorts of questions, but the answers haven't been useful or well thought out. If you know where there's a good guide, please tell me.

I have been playing for 6 wks, but I've been doing some reading, just so you know where I'm coming from. :-)

It seems a progression would be (or tell if it's not) sort of like this, although I guess it depends on the person's progress.

• Bots Intro Tutorial
• Bots Beginning
• Bots Intermediate
• PvP Normal - Blind Pick
• PvP Normal - Draft Pick
• PvP Ranked - Draft Pick (In between Custom for practice and fun with friends)

Now, how would a player gauge if he should move to another environment - by level, which level? Number of champs he can play decently enough?

I have read stories about peole going into Normal games and then, if their team loses, being flamed for apparently not being good enoough. They actually made a girl friend of mine cry. :/ Are these people just jerks? I think that could be it. The matching system attempts to group similar skill players, so there shouldn't be that much disparity in skill level, unless the complainer is using a smurf account, in which case he's the one at fault for playing where he shouldn't and then complaining.

So, what do you guys think. How do yo decide when to go up the "leagues", so to say?

Thanks.