When I was getting my road bike the store assistant suggested a small size frame, but when I tried it, it felt too small, and I tried a medium it felt right. It's best to try a range of bikes in different size frames and see which one you like the feel of best, sometimes the guys at the store are not always right. I have a pretty odd body ( shortish legs and a long torso) so a medium frame was better as I could stretch out more where I felt cramped on a smaller frame.
But just be aware that you can make a smaller bike fit, but it's hard or impossible to fit a bike that's already too big :/
Most bike shops will make you buy a smaller frame as it can be fitter eaiser. And they want to sell you a bike they already have in stock. But if it doesn't feel right don't do it
If your bike dones not fit you won't enjoy riding it, so fit should be top of everyone's list
I hope it goes well and you have many years of fun with your bike
