Congrats......
build it up slowly and when can do 15 miles at a time, don't think you have to do that twice a day for your commute.
Drive in, Ride home
Ride in , Drive home
take a day off
drive in ride home
Ride in drive home
and then slowly build up to twice a day if you feel like it
What type of a bike gear do you have?
My standard recommendation for a longer commute (based on what has worked for me) is:
Road bike, with drop bars.... more efficient, more hand positions, better ability to deal with wind
good bike gloves
Bike shorts
bike jersey -
toe clips or clipless pedals
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Life is too short not to ride the best bike you have, as much as you can.