God, of course, is Holy Other, and something completely different from anything we have experienced, but it makes sense that since we are created in the image of God, that we would reflect his Triune-ness.
Does this make sense to you?
Sense, yes. Accuracy? Not so much. There are a couple of analogies that will help you understand Trinity. One of them was by Tertullian:
Think of a great river, like the Mississippi. Now think of the river at its source, midcourse -- like at St. Paul, and at its mouth -- New Orleans.
At the source the Mississippi is a little creek. At St. Paul it is a fast flowing medium sized river between high bluffs. At New Orleans it is a slowly moving very wide river and full of silt. The river appears very different at the different places you look at it, but it is the same river. Same river, different aspects.
Or, think of the different roles you play in your life: spouse, co-worker, father, say. You behave differently in all 3 roles. There are things you do as spouse that you do
not do as co-worker or father. And things you do as father that you do
not do as spouse or co-worker. Different personalities, same person. That one is closer to Trinity in that Trinity has God with 3 personas or "personalities" in one ousia.
Now, the "image of God" gets badly misinterpreted. Because we have lost the context of the time. We always try to make it seem that some part of us is like God: our personal appearance, our spirit, His triune-ness, etc.
Instead, I had it explained to me many years ago that, at the time, "in the image" meant something very different. In those days of very slow communication, an ambassador or business factor could not always refer back to the king or business owner over decisions. It would simply take too long. So such people were given authority to make treaties or deals as tho the king or business owner were doing it. When they had this power, they were said to be "in the image" of the king or business owner.
So the phrase in Genesis 1 is about power, not likeness. This is reinforced in the next sentence, where God gives humans "dominion" over the earth. "in the image" and "dominion" are 2 ways of saying the same thing (common practice in those days, to make the point): how we as humans act on the earth; how we interact with other species, will be as tho God were acting. We have the power.