It won't hurt the baby, but I know from experience it won't be fun for you. My son was 7 months old when I got pregnant again and he jumped and hit and kicked constantly. I talked to my ob and she said it wouldn't do any damage. My second baby is a month old now and we didn't have any problems caused by my rambunctious older boy.
Baby is pretty well cushioned in there, so the impact that a 10 month old can inflict isn't going to be a problem. Just try to gently redirect her away from your belly as best you can but siblings can be pretty rough on their unborn buddies, lol. I'm expecting my fifth and there have been times I was amazed the older siblings haven't caused harm but they never did :).