I'll expand on Dennis's excellent points a bit.
I'm a big guy - NFL lineman size - and yet I prefer the GA / x14 size guitars for general comfort AND due to some shoulder injuries acquired over the years. The dreadnoughts and jumbos are mostly gone now. I can play them, but must use a strap, even when seated.
Most of us want to learn songs, not just "practice" - which I consider a dirty word. For example, if you wanted to play tennis you could run a mile first and do a bunch of calisthenics and stretching for general conditioning, followed by an hour of backhand, serving, and forehand drills. Useful but boring! Make sure to actually play tennis (have fun) once in a while. Ditto for the guitar - make sure to "play" at it a bit, which will become easier as you develop more skills and chords.
Very few people have the concentration to seriously practice a new & complex skill for more than 15-20 minutes. Concentrate on new things for a while, then back off and have some fun with it. That means picking out 3-5 songs that you want to learn, then working on them until you can do a credible job of playing them. For their second lesson, I always ask new students to come back with three songs that they would like to play at the campfire on Saturday night.
Remember that your fretting hand is an athlete, and needs both warm-up and conditioning. Just as you would never run a marathon without training first, your hands will take time to build up strength, dexterity, flexibility and endurance. Playing for an hour takes both fingertip calluses and hand strength.
Ping me at my email address: noisebuster@hotmail.com and I can send you an instructional booklet that was developed for an eight week community education beginning guitar class that I used to teach. It's not a complete substitute for lessons, but will be useful on your road to intermediate player status.