latch question/is it too late?

naraeyu

LO is 3 weeks now and this whole time i've been trying SO hard to breastfeed. i rented a medical grade pump, i'm taking fenugreek, etc. i KNOW the problem is with LO's latch, she doesn't seem to want to open her mouth wide enough no matter how many times i try!

what can i do to get her to latch on properly? 

also, i've been having to use a good amount of formula due to reasons... is it too late to EBF? is the damage done already because i've given her what i think is a bunch of formula?