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.