Hi S.,
I know you've received some good feedback and you are choosing to wait and/or seek the opinions of preschool teachers and eventually the pre-k screening, but I thought I would chime in.
I would encourage you to ask for a referral (if you need a referral to a specialist, that is) to see an audiologist. The audiologist will perform the battery of tests in the sound booth and also determine if there is nerve damage by hooking small electrodes to the child's forehead. If she checks out, GREAT! But, if there is a hearing problem identified, you can take whatever measures are appropriate for your family to ensure she is getting all of the pieces of information in speech and language to succeed in her communcation.
My little guy was identified at birth with a hearing loss and I've learned so much over the last couple of years. Did you know that even a child with a very very mild hearing loss may not hear parts of our speech and instead of using "We are going to the park", may only understand and say "We go to park" - missing out on a big portion of how normal speech and language develops. Or they may only hear "I see the bird" when you are actually saying "I see the birds".
So, I guess what I'm trying to say, is even a child with a very very mild hearing loss can miss out on large pieces of conversations - may seem small right now, but as the child gets older, intelligibility needs to grow with them.
I hope all is well with your daughter and chances are, if she's speaking normally, she's probably hearing normally - but it's better to check it out now, than realize it later.
Take Care!
M.