When I learned to fly, I was 17. Dad, flew and had a Comanche, and later a 310. I have many hours in those planes. But as a low time pilot, the main thing is: Procedures... Get a great Instructor, and practice, practice and practice more.
I have an F model, and even with all of this experience, a Mooney can and will humble you, if you do not practice with it. Most Mooneys are flown cross country mostly. We don't get much landing and takeoff practice as compared to a student pilot. Again, practice, practice, practice. If you practice, a J model or an R will be great for you.
Before, you choose, as others have stated, You must define your mission, what will it be in 2 years, 5 years and even 10 years. Try to find the most and best plane that will meet your requirements. As I found out, I have put over $40,000.00 dollars into the panel of my plane, value maybe $15,000.00. But I have the panel I want, and will keep this plane for at least 10 to 20 years.
Good Luck and Enjoy
Ron