It all depends what you work on. In small places you get all sorts to do where as in the bigger places it's all the same sort of stuff.

I've done both and prefer smaller shops. I'm currently in a small place and i enjoy it. It's not so much like a job for me, just a chance to mess around with cars. But thats because there's only me and my boss there and we tend to do a bit of everything from mechanical work to restorations. Fair enough it's mainly accident damage. But it's not a case of get the job in and out as quick as possible, it's more important to finish to a high standard.

When i was in the bigger places i was bored to tears. Always the same stuff day in day out. Never anything interesting at all.

If it's something your likely to enjoy then go for it mate. I assume your only 16? So even if you give it a go and don't like it you've always got time to try something else.