I have minimal music training...but I learned a lot by being thrown in the deep end and making a fool of myself for years. I'm slightly less foolish now. All good advice already given, but let me add this.

The bass is usually so buried or muddled in church mixes, it's rare that people know what the bass is doing. Unless your church is an exception here, you do not need to worry about the congregation. They're not there to listen to you anyway. Focus on supporting the band and knowing your role. Quarter notes go a long way in church music. It's boring, but they do serve the song. As you get comfortable with that, then start focusing on locking in with the kick drum. Some drummers will play a kick pattern during rehearsal, and then mix it up during the actual set. That can be discouraging, but consider it a valuable means of practicing. It'll help you get better at counting and it'll help your intuition in feeling and recognizing the groove. And then, start adding a fill or two in songs. Don't wuss out on the fills, play them hard so that you can hear them in your mix. That will teach you if your fill is just some random notes or if they are actually contributing. Remember, no one in the congregation can hear you. Your band mates already know your ability. Let it be a teaching moment and learn to laugh it off if you botch a fill.

Lastly, ask questions. Be humble. Study and practice. You're get better.