...is that people expect you to be older. So you can't or shouldn't do certain things that by all means you're capable of, but you don't have the age to match. And people have all sorts of misconceptions, and make assumptions about your age, which makes it difficult when they offer something to you that you can't accept, because of your age. It's ridiculous. A curse disguised as a blessing.
Not to mention that it gets tiring to always have to correct people.