Bama,
That's exactly how I used to raise my mast on my H16's solo. Did you tie your righting line rope to the trapeze wires or the forestay when lifting the mast. I always use the trapeze wires for lifting as this free's up the forestay for pinning when the mast is up. What did you tie the rope off to before you climbed off the tramp?
I'm also 51 and can't believe it

I'm 6'-1" and weigh 225 pounds. I used to be able to right my H16 singlehandidly and when I got my 18 wanting to see if I could right it by myself, I took a friend out, capsized the boat and made him tread water while I tried to right it. I came close and maybe could have done it if the wind were blowing a little harder (capsized it in approx 5 knot winds) but nevertheless, I was unable to pull it over by myself.
I now carry a righting bag if I go out by myself although I haven't had the opportunity to test it yet. I would highly suggest the same for you or some other type of singlehanded righting device before you go out by yourself again. The only way to know for sure is to test it with a friend along in case you're unable to pull it over by yourself. Make sure you're using the right technique as well. I won't get into the righting technique as it is well published and easily obtainable. I think there's even a quick note on it in the Hobie parts catalog.
Hope this helps,
Tom
H18M