I think I would do what you are suggesting, it would be the safest plan. I don't think Clematis do well inside, it might need a rest.

You might change it up to a slightly larger pot, then plant the whole thing into the ground. I have had good luck with putting potted plants in the ground then lifting them out come spring. Sometimes the place I want is not ready, or I run out of time, weather goes bad. Get the fall sales stuff so cheap I can't resist buying too much! This way is easy to over winter them. I fill the pot to the brim with dirt, level pot edge into the ground, so water doesn't pool up on the top. The larger pot will allow root growth over winter if ground is not frozen. I would cover it with a large pile of leaves to protect the crown on a special baby clematis.

Thanx, Pam and Goodhors. I planted the clematis in a larger pot, put it in the soil, and leveled the top as suggested. Now that it is May, the little clematis has sprung back healthy and growing with gusto. Soon, I will return it to my daughter. She will be pleased to see it now.