Maxperson
Morkus from Orkus
No, you can play your character however you want. That's the point. Metagame considerations needn't be taken into account for proper roleplay. If I wish to play my Strength 3 character as someone who goes around trying to prove how strong he is by attempting to open stuck doors and lifting heavy objects, telling me I shouldn't or can't do that because of a score on my character sheet is asking me to use metagame knowledge when I decide what my character is trying to do. The truth is the rules of the game allow my Strength 3 character to lift any object that weighs up to 90 pounds without any chance of failure. Imposing restrictions on my character's ability to attempt Strength-based tasks goes beyond the RAW in a way that I feel detracts from the game.
It's probably a good thing nobody has argued that, then. The truth is that your PC with a 3 strength is weak. Period. Nobody has said he can't be roleplayed as someone weak, but who has heart. The problem is when the player roleplays the 3 as if it were a 10, 15 or even 20.
Yes, it is. Maybe you just don't know what metagaming means.
No. It's factually not metagaming. No out of character knowledge was used by the PC. None. Nil. Zero. Zilch. Nada.