None of us knows enough about you to advise you as to what to do.
But, one thing we can ALL say with absolute certainty: YOU ARE NOT ALONE. Further, almost all of us have been where you are; 18, crossdressing, and uncertain about yourself.
If you're scared to go out with women's clothes on in visible view, then don't. But, there's really no reason to be scared to wear some undergarments, since nobody will see them or know you have them on but you. Many of us here frequently wear pantyhose and/or panties underneath for example.
Also; I think you're afraid of yourself a bit. Relax. You are you. Tomorrow, you will be you. Even without crossdressing, you'd still be spending the rest of your life learning about yourself.
You can't get rid of crossdressing. It's part of you. Don't try to guilt yourself into attempting to quit. It won't work. if you decide to try, don't purge (throw all all your girl stuff). Put it all in a box, and store it somewhere. You'll be glad you didn't purge when the urges to crossdress come flooding back. Purging is a waste and can get expensive. It never works.