I agree that you only need a 12 volt motor. I have a terrova which handles a 20 ft boat with ease except in high wind. Not sure that they make a transom mount - assuming that is what you need. I have Minnkota's low end 12 volt system on an 18 foot sailboat. Endura? works well.
If you see another boat in your future, consider a bow mount. The terrova with I pilot has lots of nice features, but will lighten you wallet a bit.
As everyone says, battery is important. I haven't been able to lay out for an AGM, but see one in my future. Be sure to get a deep cycle battery - starting batteries are designed to deliver lots of amps at once, rather than a smaller load over more time. . which is what your trolling motor will need.
We all love spending your money, but deep down we want you on the water!
