I ran a school club when I was 15, and we played Smash 64 as Melee wasn't out yet. Then we did Melee when it came out later. Later I went to a tournament as Game Crazy when I was 18; the people were a lot better at that one, but I placed in the top 8. Then I didn't do any tournaments until I was 27 (yep, I'm old, apparently). I don't attend many, especially because I'm not that great and I don't really have the time (or interest) to get at a level where I'm really competitive. I don't really think it matters whether you're young or old when you first go to your first tournament, but I do think that it's easier if you're younger and can devote the time to it (as long as you're not short on cash). Also, you will probably make friends if you want to and you're willing to chat with people. You won't if you don't. There's nothing wrong with either way, but if you're interested in getting to know people, an easy way to start is just by talking to people after you play against them. Ask them their name (real name and tag), whether they're on SmashBoards, if they have any advice for you as a player, etc.