If you need to start a journey, start it! Don't check the weather, your schedule, your budget, your buddy, your mood, or your Facebook! Just start for crying out loud!
When it comes to fitness, you're not competing with your best friend, or the girl next to you in Body Blast class, or anybody else. You're just competing against yourself as you strive to become a stronger, healthier, fitter, more complete person. You should be trying to be just a little better each week, each month, each year. Don't try to be perfect - just a little bit better.
I love the concept. Going really hard feels so good but it can't be at the expense of form and control. If you're training so hard that you're out of control, you're asking for trouble. An expert mountain biker can literally pedal down a mountain side, flying over rocks and roots, yet remain in total control of his bike and body - absolutely amazing! For a novice, this would be disastrous, possibly fatal.