Neither foolish nor brave!
Everyone has to pop their Track cherry somewhere and Oulton Park is a lovely track to do it on.
Just ensure you have checked the car over, plenty of pad wear left, tyres to pressure, oil and coolant levels checked etc and you are good to go.
Take it carefully on track and always keep checking your rear view mirrors as there is usually some fast metal out there that can approach fast.
Build up your speed gradually and don't be tempted to actually race anyone - it is a trackday and not a race!
Cool the car and brakes down by taking a steady in-lap before pitting and don't put on the handbrake when you pull up after a session.
If the brakes start to feel spongy, slow down take a cooldown lap and pull into the pits as your brake fluid will be overheating.
Above all be safe and enjoy the day.