Okay, so there's a number things that you really need to consider and it has a whole lot to do with your age. Have you thought about the future at all? Do you want to go to college? If so, are you going to live in the dorms? If so, what are you going to do with a tegu? Pretty much all dorms allow nothing larger than a ten gallon tank and what can fit into it. Obviously a tegu is not going to fit into a 10 gallon tank. So if you can't take your tegu to school with you what then? Have your parents take care of it? Even though you've argued to the contrary it doesn't seem to me that your parents would be to thrilled about having to take care of a large lizard for a few lizards. Especially if you go to school out of state.
There are so many things to think about. Do you know anyone who can take care of a large lizard even while you're away on vacation? Unless of course you don't plan on ever taking a vacation. I think that you will soon find out that some people who will readily drop crickets into a tank for a gecko, aren't exactly thrilled about the care and mainenance of a large lizard for a number of days. For instance, if I'm going on vacation I will seriously have someone coming over to my house for a month before I leave so that my animals are familiar with this person and this person knows enough about each animal (2 tegus and 4 beardies) that they feel comfortable feeding, exercising, and cleaning up after each of the lizards. It's very important and a point that too many people over look.
There's just too many things that a 10 year old hasn't been through yet, that you just don't know if your a large lizard is truly right for you. And it's totally unfair to the lizard for you to either lose interest or try and dump it on someone else. I'm honestly not trying to patronize you, there's just a lot of life that you haven't lived yet and you just don't know where you're going at 10 going on 11 years old.
Lindsay