HELP My baby is a month old and I've been breastfeeding since I had her. I tried an expensive MAM bottle and she would…

HELP My baby is a month old and I've been breastfeeding since I had her. I tried an expensive MAM bottle and she would not take it at all. I tried these bottles and she took it with no problem. Has anyone else used the Gerber First Essentials. It says it's a slow flow nipple but i feel like it came out really fast, she gulped it down so fast!! Does anyone think I shouldn't give her this kind of bottle being a breastfed baby or do you think she will be good using these?