My DS is 8 1/2 mo and recently started day care. He's still BF'ing so I give them bottles of EBM. But they said it's taking him about 30 minutes to finish a 6 oz bottle, which seems very long to me. He's still using the slow flow newborn nipple on the Playtex drop-in bottle because I've always been afraid that BF'ing would be frustrating for him if he got used to a fast flow nipple. But at 8 mo, he can start using a faster flow nipple and still be OK with BF'ing, right?