It sounds like it should work. Paniculatas can stand a lot of sun. But in the southern half of the country, paniculatas need to be in the shade during the afternoon (summer months only) because the leaves will scorch in no time at all. In the northern states, the sun -in the summer- is not as strong as it is here so paniculatas can be "in full sun".

You do not say where you are located so test the location and inspect the shrub often from now until the end of summer to make sure that the leaves in cirect contact with the sun do not begin to scorch. If they do, transplant it to a shadier location. Hydrangeas are quite tough and transplant well a second time as long as you try to get as much of the root ball as you can.

As popular as hydrangeas are, some nursery people really get stuff confused about them - I guess because they have so many other plants to worry about, hence a lot of details to remember. In the end, if you are in need of certain types of plants, it doesn't hurt to research the Net for ideas, reliability and performance first. It can save you a lot of time and money.

It should be just fine. I've had mine for about 5 years, gets full sun from 12 to 3, and it's just lovely. Covered in blooms. Good luck!