You definitely don't want to assist feed without experience and exhausting ALL other options FIRST.

Get your husbandry on point, get the snake feeling safe and secure and wait a few days. NO HANDLING until the animal is eating. I personally wait until a new snake has eaten 3 consecutive meals with me, without refusal, before any handling. I always advise this especially with juvenile snakes and new keepers.

Once husbandry and security is in place, try feeding an appropriately sized meal. If it is refused wait a few days and try again. You may need to try offering live a few times before switching over to F/T, but definitely don't try to assist feed again.