I am a size 22 and my Hubby is 6'6" tall and a big linebacker sized guy. We did fine on everything - except for Dinosaur. DH's knees were pretty banged up by the end, but that was height more than anything else. We have 2 preschool boys and managed to Fly on Carpets, with Dumbo, and over Neverland without issue
We even went Soarin' and had a blast. You'll be fine, and don't worry about how you'll look in photos or takiing it slowly at times. You're there to have fun and those who are there with you love you no matter what !