Normal? What to do?

[murielalex]

Hi, glad I found this forum. It's motivating!

I'm a 51-year-old woman just getting back into biking after 15 years. On pure impulse (I was making a u-turn out of a restaurant to go home on evening last week, and a car pulled out from a side street, so I swung into a bike store to avoid it, and I somehow end up with a new bike), I bought a Specialized Crossroads Sport, complete with big butt seat thinking I wanted to just ride around the neighborhood a bit. I already wish I'd saved my money as I now want a road bike, but that's a different story.

So...I haven't been on a bike in 15 years. I'm not in the best of shape, but I've been doing CrossFit (with modifications) for awhile, I have a Concept 2 rowing machine at home, and am not completely out of shape. Fifteen years ago, I commuted on my bike and had zero problems at any distance I needed (average 10 miles anywhere multiple times a day). On the day I got my bike, I started out with a light ride in my neighborhood for just four miles. I stopped to talk with a neighbor and found I was so dizzy standing there, I was afraid I was going to faint. I figured that I hadn't eaten in awhile, needed more hydration prior, etc. I prepared better next ride, and although it wasn't as dramatic, when I stopped, I still felt weak, and the same the next day. Today, I took a leisurely (average 12mph) six-mile ride on a perfectly flat road, and although I wasn't dizzy, I felt really out of breath and weak at the end.

I guess I'm sort of shocked. I've not experienced this ever before when doing a leisure ride, and I figured I could at least handle a few miles since CrossFit and rowing have can be pretty intense. I'm not experiencing any muscle fatigue or soreness, and wanted to go longer, but I was too winded. I don't want to quit. I'm just remembering how much fun this is! I'm trying to build up to my first group ride (a slow-paced, 15-miles ride with police escort in my town) in a couple of weeks, but now I'm nervous that it's too soon.
Maybe this getting old business is just showing up. I guess I'm just looking for some reassurance or ideas. Any suggestions would be appreciated.