I am not an expert at all, but I recently purchased a road bike.
My last road bike shifted on the down-tube and I have spent the last 18 years strictly on a mountain bike.

My husband is an avid cyclist so I was able to try out his bike first. I recommend getting measured because the brakes were difficult to use on the male bike due to the extended reach. Adjustments can be made.

My husband has a triple ring on his bike but he chose a compact for me. The gearing makes climbing easier and it is not as complicated as a triple. He can go into all the engineering speak but all I know is that a compact is easier than a standard and less complicated than a triple. The feminine bikes I was looking at usually offered a triple or a compact.

I chose a Connondale Synapse because it has a more comfortable geometry. The handlebars are not as low compared to the seat as in a more elite bike. The forks have more rake and make steering less twitchy.
I measured in the fit range for the 52 & 54 frame sizes. Bike shop guy and my husband chose the 54 because it would keep the handlebars at a more comfortable height compared to the seat than the 52.

My husband chose the carbon frame version, for a smoother ride, over an upgrade in components. I actually am very happy with the lower components because the 105s have this nifty little cheater window that gives me an idea of what gear I am in. The purists may scoff at me but I like it.

I am 49 and have adapted quite well. The added weight on my shoulders and arms is probably the most difficult hurdle for me. From the forum I have learned that core strength will help overcome this issue. It is improving each ride. Core strength is the cure all for just about any fitness issue!

I suggest you get a good bike fit and choose a frame designed for comfort over sheer performance.

I am not a bike expert, but I did stay at a Holiday Inn last weekend. No kidding.