Well, the theme is up to you. I turned thirteen last April and had a simple anime party with a few friends at my house with a sleep over, but, if your party is going to have about 40 people, you could rent out your local roller/ice skating rink for the day. You could also have a swimming pool party (I did that form 9th birthday. It had about 30 or 40 people in the party.) The price range will differ depending on the place you choose and the time your party is. it will probably be more expensive if you have 40 people though. Most places have a party limit of 20 or 30. You could also rent out a bowling alley. If you can't afford any of those, you can just go with the ol' birthday party at the local park thing.
Hope I was helpful! ^u^
But... 40 people = crud tons of cupcakes or multiple cakes. You should shorten it to just your closest friends and have a nice simple party. That's what I would have done. But, I'm not you. So, do as your party heart desires.
I'm turning 13 and I want a unique party idea for about 40 people. Nothing at my house though I've done that before. Nothing to expensive either.
