That’s pretty average for this age! I’d say as long as she seems satisfied after each feed I wouldn’t be too worried!
My 15 week old girl eats 4oz (breast milk) every 3 hours so I think that’s pretty normal!
My daughter is 13 weeks and we’re combo feeding as well. She eats about 3-5 oz every wake period. I’ll start her off with about 2-3 oz and assess how hungry she is and if she needs more. Sometimes she’ll get hungry mid wake period or need a little bit more to go to sleep.
My 11 week old is only eating 2-3 ounces a feed. He has reflux and has monthly checks for weight but his dr isn’t worried, just monitoring.