How did you guys stop being cowards and start living life?

How did you guys stop being cowards and start living life? I'm about 23 and it seems I have social anxiety. I prefer spending time alone at home, I'm actually starting to hate it. I have dreams of travelling and living an adventurous life but my self esteem is shit, I feel worthless and I am terrified of the world. How do I break out of this cycle?