I'm glad you brought this up.
One day a few years ago, my husband took me into a bike shop and put me on a bike and said happy mother's day. It's a nice bike, a lightweight raleigh hybrid. But it wasn't MY choice and it wasn't My idea, so even though i did appreciate it (I rode it on the STP a 200 mile ride) it left me wanting a bike of my own,,, that was really MY idea, etc etc.

I measured myself and decided that I was a 49cm person, and found a Bianchi Veloce on ebay and bought it. It's a way cool bike. it's the first road bike i ever had, and i'm still learning to ride it. I spent a fortune getting it to fit me. then purely by accident i got onto a Bianchi Volpe 44cm bike and discovered that
it felt QUITE DIFFERENT in a good way. I test rode the Volpe yesterday and yup, it's probably the right size for me. It was really funny, the volpe has shimano components and i couldn't figure out how to work the shifters.
I had to roll it back to the store and get a little lesson before i could ride it!
The owner of the LBS said to me, as you get to know bikes, you make discoveries along the way; that bikes you previously thought fit you well didn't. It's an experiential thing, a process.
when we were kids, and tremendously resilient and flexible, we could ride any size bike. But then again, did we ride 40 miles or 100 miles in a day? Probably not!

Your Giant has taken you this far down the road. Maybe now it's time to get a different bike. Try not to rush into it. But listen to the gals on here. Some of them have SEVERAL bikes now.