I started using clipless at age 58. I takes maybe ten minutes to half an hour to get used to them and I don't see age affecting the learning time much.
Used them for a few years, mostly without incident, and then last year I went to platforms. Some mid range Nasbar pedals last year and now this year I am using Pedaling Innovations Catalyst pedals. The owner of PI makes a strong (if over the top) case for platforms and his pedals specifically. I was intrigued, looked at the studies he quotes, and decided to give platforms a try. I don't feel like I have lost anything except the risk of clipless falls and the the last few percent of ultimate performance riding. The last is not an issue for me, it may be for you. The shoes are more comfortable and they stay that way all day plus they are great for walking around off the bike. If I start to get a hot spot on my feet from pedaling too long in the same position on a long ride I just shift positions for a while. You can push forward at the top and pull back at the bottom of your pedal stroke on each foot so if there is any loss in power and efficiency for normal riding I cannot detect it. If I were a racer, formal or informal, I would want clipless for sure. But for riding across country, during RAGBRAI week for example, I am perfectly happy with platforms. If you enjoy what you have there is no need to change but if you feel the urge to switch from one to the other there is no reason to avoid switching either. You might even find that you like to use both, one for some kinds of riding and the other for other kinds.