It should be cut back now, no matter what variety of Clem it is. Spring pruning is better than Fall for Clems.

How tall is it?

It is far too early in the second year to say it isn't any bigger. It is barely getting started.

Not sure if your Lowe's has the same stuff mine does, but I have had a terrible time this year with mislabeled clematis. I wanted a Ville de Lyon - which may be what you have - does it have a paler center area to each petal? - but ended up with something very big and blue. I think it may be H.F. Young. Had to keep that to go with my other two H.F. Youngs.

Went back and picked up the last one labeled Ville de Lyon. It had no buds, so I was taking another chance. Still no buds, but it has big leaves like VdeL.

Went back today to pick up another mislabeled one I saw while correcting the earlier mistake - saw two VdeL in bloom and gorgeous, both labeled Proteus. Left the store with one correctly labeled Miss Bateman, one mislabeled VdeL, and one mismarked absolutely-no-idea cute little white and magenta pinwheel type. If any of this stock sounds like what your Lowe's is carrying, I would bet you have Ville de Lyon.