Absolutely not.
Any bike will do, provided it's safe and roadworthy.
As long as your bike has working brakes and bar end plugs fitted, you're good to go.
Road bike, hybrid, mountain bike, gravel bike… I've even seen people complete our events on a fat bike!
Clipless pedals or flat pedals? Aluminium or carbon? It really doesn't matter for your first event.
The only bike we'd ask you to leave at home is an electric bike.
Oh, and don't forget your helmet – it's the one thing you definitely can't race without.