Get cracking!
I kid... I think you'll find that riding a bike is... like riding a bike. You'll be fine. I hopped back on my bike in mid July and I wouldn't say I was timid but the fitness was gone. It's still gone, or at least out of the country on vacation. I finally ramped up my riding to a "normal" workload last week but it's a lot harder than it used to be. Still.