Yeah, going out tends to be difficult for me a lot of times too, plus I´m nearly the same age as you. I noticed that my anxiety lessens a lot when I temporarily feel that other people aren´t better than me and that I have certain qualities that other people lack like drive and artistic ability. Of course this is only temporary and I can´t ignore for too long the fact that I am alone and everyone else is not which leads me back to my default state of low self esteem. When I do feel good about myself I still can´t stay in crowded areas too long or do anything extroverted so I am still limited.
I think Damaged has the right idea. I think exercise will help because it also acts as a distraction - your body and mind are too tired and distracted to care what other people think. Strong emotions, other than anxiety, also have the same effect like anger, happiness, and sadness / apathy. That´s what I noticed with me any ways. I don´t purposely try to make myself angry or apathetic but when it happens that´s what I notice.
Going somewhere with a family member also works, your attention is focused on that person more than the random people around you. I usually take my little sister to a park and go for a walk (we both love nature!).
If I want to go somewhere by myself and not deal with anxiety I will go to a park early in the morning on a weekend, like 7:00 am. There´s few, if any, people there plus I get to see a sunrise. The downside is that there´s always at least one person I have to walk past and greet and completely ruins the moment for me.
I hope this helps somewhat.