I'm sorta in the same situation at the moment. Been riding for 2-3 years...2 years ago I was just mucking around wasn't really that into it, just did it occasionly and one day I broke my nose at the local track as I was just wearing those skate helmets. She seemed ok with that.
Got a full suspension bike after that and got hooked from there. Didn't have a serious crash on that bike. Then I bought another (more expensive) downhill bike and decided that's what I want to do and for the last year I've loved every second I'm on a bike. Started to get into racing and do training and all that.
She was still fairly supportive of this even though she hates me doing it but she never liked me doing it in the first place. Occasionly gives me runs, drives me to races etc. Has never actually seen me ride she just stays in the car. Also have all the protective gear: Full face, goggles, neck brace, knee pads, elbow pads etc.
3 weeks ago when practising for Ourimbah State Round screwed up a jump and broke both of my arms pretty bad. Had 3 operations so far and just found out I have to have a 4th on Friday. As soon as I did it (after the 1st op) she said I'm not riding again.
She says she's going to sell my bikes and I'm not allowed to ride downhill (or any kind of pushbike) or motocross again. I do actually own the bikes and I buy all the parts and all that myself. Dunno what I'm going to do if she doesn't let me keep riding, it's basically what I do. I quit soccer after playing that for 9 years to concentrate on it. Haven't thought of a way that will make her change her mind yet.
Dads cool with all of it but he races motorbikes so he knows what it's all about.
Here's my left arm which is broken in right throught the bnes, the right is only broken in one spot.