Projectile Vomit - Please Help

My baby is 12 days old. She spits up a normal amount after feedings, but roughly once a day after feeding, she spits up a lot - it looks like projectile vomiting of milk and shoots 3-6 inches out of her mouth. She settles down immediately after and has no other issues. She poops and pees a normal amount, doesn’t fuss excessively, has no fever, and generally eats well. Her weight gain in the first week surpassed her birth weight. She does eat very quickly, consuming 2-4 ounces in under 15 minutes. If we sit her upright for a long time after feeding (20-30 minutes), that seems to prevent it. Should I be concerned? It’s scaring me.