Bump measurements

Is it safe to assume baby girl is going to be on the smaller side since I'm 38 weeks and bump still measures 1 1/2 weeks behind? Also, I'm 5'2" normally 110lb and husband is 5'9" 140lb so we're both on the small side. I'm just wondering because I will be cloth diapering and I only have a "one size" stash which won't actually be a great fit until around 12lb. Starting to think I should order a newborn size stash too instead of going through disposables for months. Thoughts?