I’m making good on mine so far. I decided on a short but tough one today — I climbed up a very steep and muddy hill. Until, that is, my leg muscles gave out on me. I had to basically crawl the last quarter of it because my quads just turned to jelly. I took my camera, but no photos this time — I was far to worried I was going to have a heart attack (to say I was out of breath would be an understatment). 
Never mind; it’s early days, yet — I’ll get fitter and stronger the more I stick at it. And hopefully it will all pay off as planned.