Its scary and hard at the beginning, but thats because i was hard on myself the most. Eventually you will get into the rhythm of things and everything you have to say like greetings etc will begin to flow. There are days where you will stutter and feel stupid, but i just had to remind myself that its just a job and the people i was serving were just people; and if they thought badly of me because of my speech, its completely their issue! Be unapologetic and get on with your day. You're gonna be fine :)