Don't worry about the amount you express now - by 11 months you should find your supply pretty much levels out so that you can express at will, feed on demand, and also go long periods without feeding/ expressing.
Be prepared to feed at night - when I went back to work when DS was 11 months, he would go without milk during the day (wouldn't drink my carefully expressed and frozen bm at all!) and wait for me to come home, then spend the night guzzling - but I really enjoyed co-sleeping and felt like the night-time parenting made up for the lack of presence during the day - would just latch him on, snuggle up, and go back to sleep, so it didn't affect work either.
Be prepared for your LO to take longer to get into solids than non-bf babies - and remember there is way more nutrition in your bm than a bowl of pureed carrot anyway. But all babies different...
Someone else said it - just relax and go with the flow!
I fed DS up until he self-weaned at 22 months when I was 6 months pg and I think my milk dried up- it was a very natural end to a wonderful feeding relationship but I still miss it - and nothing beats a quick bf for getting them off to sleep/ taking the pain of a banged head away/ calming an over-excited toddler down - I still miss those advantages!
Extended bf also brilliant for weight loss - but I found this only really kicked in at about 6 months. I think that's why a lot of women say it's a myth - only about 3% of babies are still being ebf at 6 months I believe, but when you are producing enough milk to single-handedly keep a lively 6 month old growing and healthy, that takes a lot of calories!