I think it's up to you and how you feel comfortable. If you don't want to cut down on how often you nurse, you can try to feed her solid food meals before you nurse (e.g. breakfast, lunch, and dinner time). This way, if you're feeding her protein/calorie rich foods (healthy, of course!), then she'll eat her fill of the food and then nurse to "top off".
I am still nursing a couple times/day my 13 month old. At 9 months, he was still nursing 5-6 times/day plus a night feeding. I would nurse then give solid foods. My dr has measured DS in the 15% for weight, but since he is growing on "his own growth curve" she isn't worried. He's just long and thin!
Another option for you could be to switch from baby food to actual solid food, if you haven't already done so. There are some great resources on how to do that, but really as long as the pieces are small enough, she can have almost everything that is healthy! Full fat yogurt, cottage cheese, and cheese (these dairy foods are ok before 1 year); meats (shredded and cut in small pieces), beans, grains, Cheerios, fruit, veggies, etc.
Do what you think is best! You know your daughter better than anyone.
There is no harm continuing to nurse her (some organizations say at 1 year 75-85% of her calories should still be from breastmilk), but there is also no harm--and some gain if there truly is a weight issue--with upping her solid foods. Even if that means keeping all your nursing times but offering solids more often.
Good luck!