Takes 3-6 months typically. Youll be fine.

I'm about a month and a half into working at Starbucks. It does have a learning curve but it isn't super difficult in my personal opinion. Cold bar is probably the easiest to learn because frappuccino pumps are based on size (usually) and the refreshers/teas have markings on the shakers.

Definitely pay attention during your training and you'll do fine. Everyone's experience is different but my personal experience was I was trained for about 4 days.

Day 1 was register and customer service & coffee brewing cycles.
Day 2 I was trained on cold bar.
Day 3 I was lightly trained on hot bar (for about 3 hours then peak hit and I was sent back to cold bar).
Day 4 I did a little more hot bar and then switched over to drive thru and learning that.

Like I said, I'm about a month and a half in. I'm now able to solo on drive thru and I'm also able to hold my own on both hot bar and cold bar. If you're nervous, remember it's just coffee. It's not the end of the world if you mess up (and trust me, you will mess up). It's just a process. No one expects you to be perfect. My shift told me that it takes 3-6 MONTHS to be proficient as a barista and as long as you try your best, that's all anyone can ask for.