How do you memorize music?

I would like to touch on one more thing. This might be the most useful information I am able to offer since I think it explains the "why" of how this works better than anything else I said so far. I feared that because I couldn't sight read that I was going to be very limited in how many pieces I would ever learn to play. As I said earlier, I can read music. But when I try to sight read while playing, my hands and my eyes are never in the same place. Maybe it is partly because I never played a musical instrument my entire life, and here I was at the age of 67 and I wanted to play piano. Ouch! But I was determined. I quickly learned that sight reading was going to be a very long and tedious process to learn. I had no desire to do that or even try. At 67 I didn't know how many years I had left to play and there is always the issue with my hands lasting without my arthritis becoming an obstacle. (Playing piano has actually been very good for it.) I have always been very good at memorizing by repetition throughout my whole life, but it never lasted. But I never needed it to. At least until I started playing piano. I knew now that I was in trouble. So, I got to thinking after I happened to come upon this fellow's videos about memorization. I was deciding if it was worth a try. I have always been a thinker when it comes to why something works or doesn't. I then thought to myself, Maria, just think of all things you know and remember. I know an entire language with hundreds of thousands of words, I know many people and many things about them. I know tons and tons of stuff! So why can't I memorize tons of songs! Well, the reason is clear. I haven't memorized all of this stuff I know throughout my 71 years of life. I remember it! And that is why I still know it and why I believe this method works so well. And the fellow who teaches this on youtube has never said this, but I will. Skills and knowledge that work long term may not be memorized skills at all. They are things you remember! I believe this is successful because you are not really memorizing a song so much as you are teaching yourself how to remember it!  That is why the struggle to remember that I talked about in my original post is so important.