Apologies if there is already a thread for this, I checked the Covid topic list of thread titles but couldn't see one.
Calculate your Covid Age here
This table starts with your actual age and then adds (or subtracts) years according to your particular vulnerabilities, which gives you a "Covid Age". So if you are actually 35 but have a Covid age of 75, you should be treated as having the same vulnerability as an otherwise-healthy 75 year old. Scrolling down the page further it then gives estimated risk and fatality rates for the covid age you come up with.
I found this useful.