Do I have to have a parent to go

I'm sure if your around 15 are 16 your mature enough to go alone provided that you have the money to pay your way in and away to get there and home! They dont have food inside but on the outside all around them there are places if you get hungry but you need a good 80 dollars 20 to get you in

It depends on your age.

Yes depending on age and the ticket booths are in the front off to the left

I would say no. But I'm not sure what the ticket booth rules are

If you are of responsible age, no. Be at least 17.