While much of what it is does sound extremely Yoga Flow Review'airy fairy' and 'new-agey' if you take it with a pinch of salt and keep an open mind you can get a lot out of it. You don't have to immerse yourself into the philosophical and spiritual side of it to feel its benefits.
For a start, yoga is great exercise and it's a great way to stay flexible and limber (especially as you get older). It can also help develop your core strength, since some of the positions are extremely demanding. That being said, one of the core principles of yoga is that you should never feel any pain when practicing it, whether you're an expert or it's your first time doing it.
Yoga is basically about going through a series of different position, each focussed on stretching and opening up a different part of the body. It's usually done on some kind of mat for comfort, and is meant to be a form of exercise that helps calm the mind and focus oneself.