Is it normal for my 1 1/2 month old not to poop everyday like she use to?

Yes. At about 2 months there's a growth spurt. Some breastfed babies won't poop for a week.

@babyrsmommy, if she's exclusively breastfed its perfectly fine and common not to have a bowel movement for couple days. My son would go sometimes days without.

@nurseriri, I breastfeed my baby and here and there formula feed her.

@babyrsmommy, as Long as her tummy is soft and she's not fussy it's ok. But monitor. Good luck