Been thinking about grabbing Dawnguard for PC (got Skyrim for Christmas) to expand my vanilla experience. The thing is, I don't want to start a completely new character, so can I simply install Dawnguard and continue from where I am currently? I know uninstalling is not a good idea, so once it's activated, I'll be stuck with it unless I revert to an earlier save. After reading some non-spoiler threads, it's been hinted that levels 15-20 are the best time to start the quest at, and that's where Demeter is at the moment (after ~50 hours, though!).

No. When you activate Dawnguard, its content will be added to your current game and you can continue playing with your character

Thanks.

Not at all. I'd just finished vanilla Skyrim when I installed Dawnguard. I just activated it and the next thing I knew a Whiterun guard was telling Chadric that the Dawnguard were reforming! Smooth as silk.