Good Morning, 

Thank you for contacting the U of M Extension Service. 

I did not see a green ribbon on your leader. 

Here is a link from the Missouri Botanical Gardens about Korean Maple: https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?taxonid=275369#:~:text=Acer%20pseudosieboldianum%20commonly%20called%20Korean,areas%20in%20Korea%20and%20China.

This information states: 

Acer pseudosieboldianum commonly called Korean maple is an upright, deciduous, small tree or large shrub that matures over time to 15-25’ tall with a similar but sometimes wider spread.

I believe the growth traits of your tree will be a wide and short tree. You may not get a tall leader. The tag or literature you received with the tree should talk about the growth form when you purchased it. 

The above information indicates the height and spread of the canopy are both between 15' to 25'.   

Here is another general link to pruning trees: https://extension.umn.edu/planting-and-growing-guides/pruning-trees-and-shrubs

Good Luck!

Good Morning Shella, 

Based on the above information about the growth shape of the tree, I would quit pruning it this year. It is the first full year of growing. It is supposed to be a wide canopy. 

I would wait until late winter, look at the shape and prune based on the link I sent earlier.  You might want to prune up some of the lower branches at that time. 

Good Luck!