how old would you be

If you could decide what age you were able to be, maybe even for as long as you are alive or breathing, how old would you choose to be and why?

I would be 18 b/c here in the US you usually are graduating or just have and so you basically get to begin your life over agian and have a clean slate if you want. It's a good time in my opinion and you get to vote, get tattoos, live on your own, etc.