I'd suggest easing into it. Going from zero to 23x5 in a hurry could lead to injury. Maybe do it once or twice a week to start, build up to 3x then eventually to 5.

I'm also guess you'll find hills you didn't even realize were there. Having lived in the area, I know it's not entirely flat. Even here in Manhattan where I do 7 miles round trip every day, I find hills that wind me pretty good. That said, I think my commute could be 2-3x longer if necessary and I'd still probably do it daily.