I'm 55 years old and did the same thing! Here is the story...
I raced my 450 at Freestone earlier this year. After the first moto, I came in and my wife says, "That is the worst I have ever seen you ride, I was embarrassed..." She was right, the track was super rough with deep deep ruts and I was struggling. A few months later, my 450 was down so I hopped on my sons 250F. I come in after a short ride and my wife says, "you look way better on a smaller bike, why don't you get one instead of your 450..." I started thinking and then decided to go all the way down to a 125. Inspired by Robbie Reynard and got the idea to race it at Loretta's this year. I won my area qualifier on my 450 then sold it, bought the 125 and raced it at the Regional and made it to Loretta's. Love the bike and can ride it longer with better lap times than my 450. Loretta's update: Crashed the 125 two weeks before Loretta's, resulting in a fractured left distal radius. Took me out for 6 weeks, I've got 3 weeks left.