sending a confirmation email instead of my welcome flow

Are you referring so a subscription confirmation to your email list or your order confirmation email?

a) If list subscription, its likely because you have double opt-in enabled on the account. This has positives and negatives, if you want to remove it go to your account settings and disable it. (see screenshot)

b) If your talking amount order confirmation, than its because your order confirmation sends from your e-commerce provider unless you've migrated it to Klaviyo. It will always send before your “customer welcome” flow if thats what you’re referring to.