Are you powering your circuit from the USB ports +5V?
If so, it's likely the delay is in your reset circuit on MCLR.

Quite often people will put a capacitor on MCLR, thinking it will be more stable and not reset.
But instead it just adds several seconds to the power-up reset time.

MCLR is usually a Schmitt Trigger input, so the capacitor has to charge to over 4V before it releases the PIC from "RESET".

If you have a cap there, try removing it.