Don't worry about what you take your supplies in and take the machine you know how to use and feel comfortable with so you can focus on learning.
And definitely sit in the front or close to so you can see and hear easily. I'm sure you'll find your "tablemate" will be friendly and you'll have a great time.
No matter how long I've been sewing and how many classes I take I always have a great time and usually learn something new also.