We had a fabulous time riding Courthouse with Sam and Marla this AM. They did a fabulous job of managing a group of 7 total newbies with a wide range of ages (3- 20-somethings; 2- 50-somethings; 2- 60-somethings) and comfort levels in learning the bike and navigating the terrain, keeping us all smiling and learning and safe. We took frequent breaks to regroup, take photos, and listen to instruction for the next segment of the trail. At one point the group split so that those ready for a bit more of a challenge could try a somewhat harder trail. It was a great introduction to the sport; we (the 50-somethings) learned alot and gained alot of confidence - we'd love to do it again!
In terms of fitness level required, it was well within our abilities -- I'm a runner and we do CrossFit together a few times a week. If you're older and regularly physically active with some intensity, you'll be fine, physically, and the primary challenge will be the mental part of trusting the bike and committing to powering through the terrain. Regardless of your age, if you're out of shape, it will be much more of a physical challenge in addition to the mental one. The obstacles are not hard but they are different from anything you've ever done before if you're new to mountain biking ... so sometimes it doesn't work out. You're not near any real hazards (e.g., steep drops) - the worse that happens is you fall off your bike (unless you brake too suddenly and flip yourself over the handles ... almost did that ... all my fault not the obstacles' ... not recommended ... managed to let off just in time...). If you try and fail, you can try again, or walking past it is always an option. We had a couple of times where people tried, failed, and either circled around for a second go, or just decided to walk -- either was fine. Regardless, you're out there doing it, learning, and having fun with some great coaches.