If you have never done it before at the age of 63 then as a coach I would advise you try a Beretta Urika 2 semi-auto with 28gram cartridges. You can buy a perfect second hand one for around Ł700. They are very good guns. They are multi-choke and have an ajustable stock via shims on and in the stock. They have no recoil with 24gram cartridges and very,very little with 28grams but will take the 3 inch magnums for high goose shooting if you need to. I use one for coaching and the more mature first time shooters do prefer it to the over and under.
Pop into a gun shop and ask if you can try one.Get the 28 inch barrels as any more will be too much for you on an semi-auto.
If you have a shooting ground with a gun shop on site near you that will be the best place to go.
Good luck.