Welcome to TE and to commuting!!

It kinda depends. Can your ride 14 miles right now comfortably? If so, then 28 should be no problem since you're splitting it in two, with a little work thrown in between. Also, if there's the possibility of catching a bus along the route if you find yourself running low on daylight or energy, or the weather just turns sour- that would be a great thing to have as a back-up.
If you're in good shape already, then I see no problem! Sounds like the perfect way to get to know your new city, and to get some great exercise/stress relief in every day!!