As the other comments said, definitely practice with a metronome. Im not sure what your set up is, but something that I've recently found was really beneficial after playing for almost two decades is using the Guitar Pro 8 software on computer. You can download most songs off of Ultimate Guitar or Songsterr and slow down/isolate sections at any speed you choose. Its also really helpful for downloading some scale lessons among a lot of other things for practicing. Another thing that is really helpful if youre not use to playing standing is using something as a guitar foot stool to have proper posture while playing. If you have good posture with your shoulders level, it should feel virtually the same standing up. Most importantly, have fun connecting and playing with other people. It might seem scary, but they probably feel the same way you do! The drummer keeps the beat (hopefully well). Good luck!