A.B.
You'll be fine. I pumped with my daughter for a while since she wouldn't latch on and it was just too overwhelming for me. I started making her bottles half my milk and half formula for a while, but every now and then if she would get a good latch, I would BF too. She ended up on full formula after 3 months old. She was fine and perfectly healthy and she is a very bright, healthy 22 month old now.
I am due in July too and I plan on BFing but supplementing formula bottles once a day so that he is used to bottles. I have heard of situations where babies will not take a bottle at all if it is not introduced soon enough and I have to go back to work in 2 months. After I am working, I am hoping to BF morning and night and formula feed in the day. If my milk supply is running low, i may pump once a day at work.... we'll see.
The point is.... it's TOTALLY fine!