Hi Penny, well done on jumping in and posting - don't worry about getting things in the right place that's what the moderators are for.
As Ms W has said, your kids are at great ages and will love the trips. More importantly you'll get to meet other single parents while your kids have fun. You won't be on your tod at all, rest assured everyone is nervous on their first trip - there's a great thread on here about joining in and how each of us was terrified at first but how the trip was fantastic! Each trip has a co-ordinator who gets everyone together and before you head off on a trip you're sent details of who is going (first names and ages of kids). Above all, everyone there is in the same boat so will know how you are feeling.
Hope to see you soon xx