Solids and vomiting

Kalen
Hey Mamas!
My pediatrician wanted us to start solids at 4 months so my little can gain some weight, she's on the petite side. I read that you should give solids when they are hungry but the possibility of supply dipping. Then I read that you should feed after a nursing session. Well last time when did that she vomited EVERYTHING up... twice. She's not allergic since she has had avocados before but I've fed her them while she was hungry so no upchuck. So I now feed her solids when she gets hungry.
Anyone else ran into this?