I commend you on your desire to learn to play guitar. It is a very versatile instrument and can provide a lifetime of enjoyment at any proficiency level. But it is not the easiest instrument to learn to play because of the need to train your brain to get your hands and fingers to contort in very un-natural positions, not to mention tender fingertips against steel strings.
In answer to your question, guitars come in all manner of different shapes and sizes - even among what is considered a full sized or full scale guitar.
Many acoustic guitars are of the dreadnaught shape which is quite large. I have a dreadnaught guitar but find it a little more cumbersome to play than my concert body guitars that have a narrower waist. Some folks like the big boomy bassy sound of a dreadnaught.
In addition to varying shapes, acoustic guitars also come in varying depths. I generally prefer a slightly thinner body guitar personally as it is more comfortable to hold and play.
In addition to different body sizes, full size guitars also come with different neck profiles, widths and thicknesses. They can have a C shaped neck or a D shaped neck or a V shaped neck. I personally prefer a C shaped neck as I have smaller hands.
Neck widths on an steel string acoustic folk guitar can range from 1 5/8" at the nut to 1 7/8".
There are also full scale acoustics that have a neck that joins the body at the 12th fret instead of the 14th fret. These may have the same scale length as a 14 fret but a longer body with a different orientation of the sound hole relative to the bridge.
Here is an example of some of the different shapes you might find on a full size acoustic guitar either in a standard 14 fret or 12 fret configuration.
If you feel you might benefit from trying a slightly smaller guitar, many of my students love the Taylor GS Mini. It's slightly larger than a 3/4 size guitar but has a very full sound and comfortable neck profile.
Here is a link to the Taylor Website GS Mini Page Taylor GS Mini
You can find these used for less than $400 and new for under $500.
You might want to visit a local music store that carries a large variety of guitars and just try out as many as you can. I would stick with the smaller waisted body styles (like the grand concert or the auditorium 000) though if playing comfort is important to you.
Don't become discouraged by a guitar that makes it more difficult to play. Keep playing the one you have while you shop for one that is more comfortable to play.
You may also want to read this How to minimize the pain of learning to play guitar
Good luck on your journey to learning to play this wonderful instrument we call the guitar.