2 years ago I was the same way. Stayed away from the park and just freerode to avoid any injuries. Last year I figured, why not, and started in the park. Started small and tried the larger jumps as the season went on and I had a great time. I only regret not trying it sooner.
I would get as much insurance as you can but be aware of the different kinds.
Health Insurance: This will pay *most* of your medical bills. You might have to pay a deductible and co-pays, but its a lot less than paying for the whole bill.
Accident Insurance: There are many types. I have one through work which pays whatever my health insurance doesn't cover (deductibles/co pays). They will also give you extra for a broken bone or other problems.
Short/Long term disability: This will typically cover your salary (plans vary - some pay 100%, some less). The plans vary, but Short term usually kicks in after you have been out for a week or two, and will stay active for just a few months. Long term typically kicks in after a few months (typically 3 months), but will pay out for a longer term.
As for what to get all depends on your situation. I have a good health plan at work so I only have to pay a $500 deductible. I did get the accident insurance since it was so cheap. Between the 2, if anything happens, I won't have any medical bills. My company also provides me with a good short term disability plan so I will get paid 100% for 3 months (after I'm out for 1 week which I use personal days for). The only thing I lack is a long term disability plan which I really should add.
All that being said, look to see what your employer provides. You might be able to get a decent rate on some additional coverage (or have it already - many employees here didn't realize they had the short term disability).