Hesitant to buy new born clothes

Tomorrow I find out sex of baby, and I'm definitely going shopping after but my last ultrasound I was 17 weeks and 4 days..but my baby was measuring 19 weeks (baby has measured big every ultrasound except the first two) And I keep hearing stories from my MIL about how my husband was 10lbs at birth and didn't fit newborn clothes...so I don't wanna buy a bunch of newborn clothes and baby not fit anything. Any suggestions from mothers who have had big babys or are possibly pregnant now with big baby?! Thanks!