Feeding older baby newborn milk

Those of you with a stash to feed to baby later, was your baby ok and accepting of milk from when they were a newborn?

My baby is 7w tomorrow and I have an ok stash, I am able to pump atleast 2x a day for an extra feeding that I freeze. I’ve heard some babies will reject the milk from when they were a newborn and I have a decent amount from when my baby was 3-5 weeks old saved up. I’ve been thinking about using some of it now and just replacing the feed with a pump because I’m worried she won’t drink it when she’s older and it will help save some space since the bags from last month are only 2-2.5oz each and I’m pumping more than that and can save bigger amounts in a single bag now. But mostly I’m worried about her rejecting it later if I don’t use it now.