I'll add to all of the above the Sea Otter is not a good race to pick as your first. It's a brutal course and it's a big race so it attracts a lot of stronger people. It also gets a lot of strong mountain bikers doing there annual cat 5 road race

There's nothing like a pro mountain biker stringing out a rapidly disintegrating group up the climb and then descending with a bunch of noobs through the corkscrew.
They don't call it Sea-Slaughter for nothing...