while you may be able to express enough to feed baby BM bottles i really wouldnt expect to.
(but yes some people do do it)
I have 3 breast pumps, hand, swing and a top notch hospital ones. Over 3 expressions i get perhaps 6 / 7oz MAX a day (my baby drinks 1 8oz bottle a day now)
If i express instead of feed i get nowhere near a feeds worth of milk instead, just maybe 1.5oz per breast.
My baby is 4m old, and still has 8 / 9 feeds per 24 hours, and i just could not express that amount.
(Daddy gives her a dream feed bottle at night)
expressing is time consuming, a real faff and a pain. feeding direct from a boob is so much easier / quicker.
If you are embarassed about feeding front of people get a bebe au lait / nursing apron etc (then no one can see anything)
Or just tie a muslin to your bra strap and cover your self and baby that way.
Agree about going to a BFing group (you can go before you give birth, they wont mind)
in the early days baby will be feeding very very frequently so you will either have to have no visitors at all, or feed / express infront of a chose few.
to express you need your boobs fully out (and with a double pump thats both) when you breast feed a baby, the baby covers almost all the breast anyway 
Its great that you plan to BF your baby, but i wouldnt expect it to be easy to express every bottle you intend to feed in public 
I have BF my baby in public since she was 6 days old, and most days she gets at least 2 of her feeds while out and about and i can honestly say no one has ever said anything / looked at me funny / made me feel bad / awkward, or even batted an eye lid about it.