Pacifiers for my newborn?

My baby is 6 weeks old. She loves her pacifier from the hospital i'm sure the majority of babies have the same one (soothie) its blue. Anyway, I bought different ones at walmart a completely different brand and she will NOT take them they fall out of her mouth as if she cannot latch on to it. What should i do? will she eventually like other ones? I did buy soothes at walmart after she denied the regular pacifiers and they only sold 3 months+ and they are still too hard i think for her to latch on. any suggestions? When is a good time to take her off the pacifiers and how?