Ride whatever you have, enjoy it and don’t worry about what everyone else says or does.
When you get to the top of the climb you’ll be amazed at the different shapes, sizes and values of bikes getting chucked down the hill. Every single one of them will have someone sitting on them grinning.
Just to give you some context i’ve never felt out of my depth on my full on XC 100mm hardtail 29er. As long as the brakes work well and your tyres are half decent you’ll be fine.
It’s just riding after all.