The minimum age to sign up for most sites is usually 18, but there are some that require an older adult (21+) be present during registration.
Hopping on the internet is a huge responsibility. When you sign up with an online casino, make sure that your age fits what they require for registration! Lying about it will result in getting found out eventually and often times this means whatever money deposit or winnings might have been won can easily go back into play by being reversed from our database.
Just because you're not old enough to get a license doesn't mean that it's too late. It just means patience, and waiting until your next birthday!