Staying in and babysitting

My wife really loves going to gay pride and as her friend couldn't go as she couldn't find anyone to babysit her children I volunteered as I quite like her children and last year pride didn't seem as good as previously. It's a good deal really as I get to chill out this weekend and they get to go out and party. I wonder if I'm getting too old for this kind of thing? At least its good practice for when we may have kids!