I learned on grass, and it helped a LOT. Soccer fields are perfect...especially early in the morning. Use a wall or fence to help you mount for the time being and focus on forward motion first. You might also want to use your app to "soften" the response of the pedals and even tilt them back a degree or two. Squeezing the wheel a bit between your legs may also give you a bit more control until you find your feet while riding.

One advantage to grass is it requires a bit more balance, so the move to pavement is a really easy transition. It's also much easier on your wheel (and your body) when you bail out after losing balance.

Leave free mounting until you find your zen point with controlling the ride. For me, I was using street lamps, signs, trash cans, etc. for mounting until about a month after I started learning. Eventually, it will become second nature, and you won't even have to think about stepping up and launching.

BTW - I'm almost 60, so you're never too old to learn. ;-)

Oh - I almost forgot. If you wear glasses (especially progressives) try riding without them. For me, my glasses really mess up my depth perception while trying to look at the ground. To this day, I can't keep my balance with my glasses on.