I Just Applied At Sears, And Was Able To Set Up An Interview Date (all Online Btw),is That Good?.. Help?

So after i finished the question assessment online, they asked me to pick a date for an interview, then i got an email confirming the interview…So my questions are…
1. Is that good?
2. Should i call back to actually confirm it has been set up?
3. What should i wear for the interview?
4. Got any tips for me??
Thank you guys soo much..
Btw im 17 years old and never had a real job before.