When I started giving my girl formula it took around 20 minutes to down depending on how much. I typically stopped to let them burp halfway through their feeding. Make sure they burp before continuing so they get the gas out. Your definitely not a bad mom your learning as you go. For the vomiting maybe you’re giving them too much formula for their age. My daughter at that age was drinking 3-4 ounces every 3-4 hours
Make sure you have a 0 tit!!!
If baby is used to BF they might be a little And often type. 60 is fine, but i would be offering every 2 hours. What bottles are you using? Dr browns or mam Are good
They shouldn't be downing the bottle, but it shouldn't take too long either as they may fall asleep. You are definitely not a bad mom. Just make sure you burp after the bottle. My son was tongue-tied, and the midwife said paced feeding is good for babies. Perhaps have a Google into it. We used it for all of my sons bottles xx