Well, I have 6 kids, and I just turned 31, so I get it coming and going--"are all those yours???" AND "you're HOW old???" But my biggest challenge is just the vehicle to drive. We're going to need to size-up, as while we all fit in the minivan, we can't take DH with us anywhere. ;)
Apart from that, I don't really have major issues. I do get sick of all the comments, but frequently, especially from older people, I get "what a lovely, well-behaved family/kids you have," which is always heartwarming. :) My gut reaction to most things that people say to me about most things is "you have no idea what you're talking about," so this additional thing doesn't really bother me.
My biggest challenge at home is that well, we're messy. I am, DH is, and we have produced 6 messy kids. Now, although I am messy myself, I still get SICK of the constant drift of debris I am forced to live with. If you're naturally neat, you probably won't suffer from this issue.
Enjoy your bigger family--you'll have more friends when they grow up! ;)