First time TS Security Clearance

Apologies if this is repetitive, my record is sponge clean. I completed the process at the start of December and only received an email asking if I was still interested in the position. (It's my first job so I'm anxious and nervous). I've read within a month ppl usually get an interim clearance. Are the holidays to blame for the delay etc. I've read some ppl mention references causing delays(idk what that means).

Any and all advice would be appreciated

Edit: Is it usual? And should my references be constantly aware of some sort of notification?