Hi Jam & Hershey!
4 month old is not too late for the ears to stand up. Just keep them trimmed to keep the weight of the hair off her ears and they should be just fine. Yogi (he's my avatar) has
a ton of hair and I actually have to keep his ears trimmed nearly to the base right now or they'll flop. Also, you may see them sort of fall during her teething times, so don't be too alarmed if that should happen.
Can't wait to see pictures of your sweetie!!