[dazzawazza]

Hmm, how long is a piece of string. It's a difficult question to answer. Why not ask your peers? If you trust them and they trust you they will be honest and you will learn. If you don't trust them leave.

For fun you can look at http://projecteuler.net/. Project Euler poses a series of problems for you to solve using a language of your choice. Of course you'll need to get your peers to do it as well but the different approaches to each problem can be very revealing. You can learn a lot about your abilities by reading the comments in the forums which are unlocked when you complete a task.

As a side note remember that the power of most programmers is unlocked within a team. Some 'lesser' programmers shine within a team and fail on their own. The reverse is true also. I know many excellent programmers that are near useless inside teams of non-programmers and a few that can't work with anyone.