What do you think about me having to pretend and act like a kid in a 35 year old body?
What makes you have to pretend to act like a kid?
I was friends with a very beautiful woman and I felt like I couldn't do anything but pretend to act like that.
It's okay to do fun things with a friend. If the activities that you are doing feels childish to you, perhaps it would be best to discuss this with your friend. Talking about it will help to find fun activities that you both will enjoy.
I think I would have more fun with her if we just remain friends with benefits.
It seems you want to have more intimate interactions with your friend. Talking about what you both expect from your friendship is best. This way you won't be pretending to enjoy her company when you're not.