Age for oral food challenge for infant-onset shellfish/shrimp FPIES?

Hi! Title basically says it all, but here’s my situation.

My toddler had projectile vomiting 4hrs after eating shrimp on 3 separate occasions, so her pediatrician and I both agreed it’s the likely FPIES. That was around 15 months. She’s 20 months old now.

I’m not ready to do an oral food challenge yet, obviously, but I know shellfish FPIES is more stubborn. What age did you, or were you told to, schedule a food challenge?