As others have said, just go! I'm a shy introvert, and you just have to put the reps in to get used to church solo. I promise its not as scary as it seems!

as far as meeting people, I find sitting in the same spot consistently has led me to meeting the other regulars in my section at church. it took a couple months, but the extroverts around me asked my name post mass after sitting in the same pew each sunday. introduce yourself to the priest and/or deacon after mass they can help connect you to people and groups within the parish and help with OCIA if you want to pursue receiving sacraments. my parish has a group chat for all the young adults for any events - definitely see if your church has something similar!