When should I assist feed?

Hi, hope someone can help me.
I have a albino black pastel female ball python and when I bought her 8 weeks ago she weighed 240 grams but hasn't fed in the 8 weeks I have had her and she now weighs 222 grams. Should I assist feed her? She's looking thin and I have changed her enclosure a few weeks ago hoping it would reset her but still no improvement. What should I do?

How many times did she eat for the breeder? Do you know how the breeder sets up babies (I will assume racks)?

Also, what exactly did the breeder feed this snake, & are you only offering the same prey, in the same way? This is very important for some snakes, & usually helpful for all.

Are you handling this snake at all? If so, stop, until after the snake is eating reliably (3+ times without refusals for anything other than being in shed).

I agree with what was said above, need some more info on what's going on.