My boobs didn't grow until after the baby was born and I had an oversupply. It's way too soon for you to worry about this.
Wait until after baby. Your boobs will blow up
You may want to at least research 'insufficient glandular tissue'. It is really misunderstood and most lactation consultants are not educated on it but there is a wealth of info online. Little to no breast changes is a big indicator as well as physical characteristics that you can look up online. I found out after my son was born that I have igt and wish I knew about it before. Hopefully it isn't but you can at least rule that possibility out :) good luck mama!
I would not worry about that yet your milk will come after you have your baby.
You won't have any milk until after baby arrives, they just need colostrum the first few days and that's okay! I wouldn't worry about it, you still have plenty of time for your body to make what you need. Newborns' bellies are tiny and they don't need much