Cycling to get in shape

About a month ago, I picked up a Specialized Ruby to help with getting in shape and improving endurance. I had cycled in the past, but just for fun on my vintage 60's Schwinn. Having a carbon frame road bike with some Enve wheels is a night and day difference! So much less effort to go, which means I can go further and really work on building the endurance! 
My goal for the end of the year is to do a 50 mile ride. And I've actually been enjoying cycling so much, I am joining in on one of the local races!