Yep, actually this year makes it 40 years, started with a little cutting in 1974. Yikes, I was young and skinny then. I'm not now.
In a pot for 40 years, it is still only slightly over 1 inch in trunk diameter, about 14 inches tall.
It is the tree I made all the beginner mistakes on. One big mistake was not understanding how to use escape branches to thicken trunks. That is why after 40 years it is so thin. It could have been any size I wanted, even in a pot, if I had understood the technique while the tree was young.
Since you are in Missouri, you will have to keep it in a pot. I only leave mine out to get a light frost, just enough to knock the leaves off. Then I put it in a cold cellar, 32-40F for the winter. Usually by late January it shows signs of wanting to grow. I hold it in the well house, cold, until spring. But if you have a greenhouse, leave it out to a light frost or two, then put it in the greenhouse. It will sit dormant for a while, then wake up with a nice flush of shoots. If you can spare the space, let it become a shrub, with roots to fill a one gallon to 3 gallon pot. While it is young, chop it low and let it branch out and bush out. It can tolerate being chopped as low as a couple inches above the soil. Let a low branch and one branch higher up toward the crown escape, grow long. Prune the rest short as per your thoughts to design. Let the escape branches go for 2 or 3 years, until they are 3 to 5 or more feet long. This will thicken the trunk. Then cut them off flush to the trunk, pick another low branch and let that go. Repeat as needed. You seldom see photos of this technique in use, because while all the better artists use it, they seldom take pictures because it looks ridiculous. There is plenty written about it, search this sight or "the other sites" for "sacrifice branches" or "escape branches"
You can have a pomegranate with any thickness you desire for the trunk.
I think pomegranate is a great tree for the novice and the expert. It survives accidental total dehydration, neglect, wrong season repotting, and all manner of abuse. The only thing it really does not like is deep shade and temperatures below 25 F. If it looses it leaves due to drying out or other insult - don't use it as kindling, let it sit for at least 3 months, sometimes they will come back from what seemed like certain death. I had one come back to life after being totally dehydrated for over a week - and I mean totally bone dry. Normally that is certain death for many trees. It took a while, but all of a sudden, there was life.
They ramify well. Have neat flowers and fruit. Have fun with it. And cuttings root easily, you can always make more. Make a spare to two. Go wild.