You've got to start somewhere! If you're interested in learning how to get upside down and relate with your world in new way, check out this quick video on how to do a headstand (sirsana A).
Check out these additional tips that didn't make it into the video.
1. Working at the wall.
If you're really timid about working this pose in the middle of the room without a safety net, then practicing near a wall can provide you with support. But make sure your wall is just that, a safety net! If you use it as a rebounding board to kick up against and then and bounce back from to get into the pose, you'll never learn to lift up without it. Set yourself up about 10 inches from the wall and it'll be there just in case you feel imbalanced. Try to pretend it's not there at all so you can build the strength and proprioception to lift up on your own.
2. Kicking up.
If you don't have Gumby-like hamstrings like I do (and I'm not gonna lie, flexible hamstrings make lifting up easier) then you'll likely be tempted to kick your way up into the pose rather than use strong arms, legs and abs to lift up gracefully. I think it's ok if you give a light hop off the floor but if you've started full-on donkey kicking and can't make it up (likely at the wall) then you're running the risk of injury. In yoga we want to move with control and ease rather than force and coercion. Work with your teacher to increase your abdominal strength, aerial awareness and hamstring flexibility so you'll be able to lift up with ease, eventually.
3. Learning to fall.
It's part of life! Usually once you fall out of headstand once, it will rarely happen again. Your body gets used to exactly where it needs to be and creates a memory so you'll give just the perfect effort to get up each time. If you're afraid to fall, try practicing on a carpet with pillows around you or up against the wall. It's likely you'll do a little somersault and have a case of the giggles after it happens. Because somersaults are fun. Then get up and try again!