Fear is something you have to learn how to control. The fear of new rails/jumps is completely normal and no one was totally comfortable doing it for the first time. I've been riding for a long time but recently have been doing street-style rails (from the side) and it scares me every time when it's a bit higher jump to get onto the rail. I'm guessing these are the rails you're wanting to hit later since you said you can already do ride-on features, but for now focus on getting boardslides down on ride-ons. Personally it's always in the back of my mind that I'm going to clip the street style rails coming onto them but you have to push that aside when you get to that point. I'm a firm believer in the deep breath approach...and it's just that. As you're approaching the feature, just take a long deep breath, you'll be amazed how much it helps.
As far as what you look like to others, doesn't matter. Other people don't care. It's that simple. Unless you're sitting in a landing or blocking a rail, no one is going to give you a second thought. You're just another rider on the slopes. When you're crashing trying the simple park stuff, just laugh at yourself. As Snowolf said don't take things too seriously, go out and have fun with it. The people that take things too seriously are usually the ones that don't stick around too long. I had to check myself on that today because it took me 31 tries to get a taller street-style rail in our park to the end. I know if I would've gotten all stressed about it, and worried what I looked like, I never would of got it. Focus on what you're doing, not what you look like doing it.
Remember, the people you might think are judging you or the people around you making you feel embarrassed may be the same type of people on this site giving you advice