Yes it’s unusual - an inheritance if that size would usually come from a parent and most people still have a parent living at that age.
It’s also unusual to get a £100k gift
Idk why it matters - some people get large gifts and inheritances and others don’t. My friend got an absolute fortune at 21 from a trust her gf had set up. He was long dead and all his dgc benefitted at the same time but she was the youngest - oldest was pushing 40.
I wouldn’t particularly want random people knowing so re the car I would say “my mum gave me some money from an inheritance she got so I spent it in this car” which is honest but gives the impression the money has gone.
There is a massive variation in income and assets. No point comparing your situation to others.