I have a Trek Hybrid (7.2 fx) in 17.5" and measure 164 cm. It's just the right size for me.

The fit will depend on your legs and torso length, but I find that generally beginners (I don't know if you're one) feel more comfortable on a smaller bike, something about a greater feeling of safety. But that may cause some issues after a few weeks if the bike does not fit right.

You may want to try a few other sizes and see how they feel. (I know it may not be obvious for you.)

But above all: resist buying a bike because it's on sale and a good deal (unless it's your 10th bike!!)

Good luck!