Yes she looks pregnant but maybe just starting to show. If it's her first pregnancy it seems like it takes forever before she has them. After the first time though you can expect her to drop about every 30 days. Even if you don't have any males she'll probably have 2 or 3 batches from stored sperm.
If you are putting her in a seperate tank (as opposed to a breeding trap) you can move her any time. Just try not to stress her out chasing her with a net because she might abort. I've never used an actual breeding trap/net thingy because from what I've read it's more stressfull. I either move mine to a separate maternity tank a week or so before they're due or let them have their babies in the main tank. If they have them in the main tank I usually net the babies out and put them in a fry only tank.