You can try to schedule the load every 13 weeks, every Sunday, for example....
It's not perfect, but close enough...
If you need to do more accurate task (exactly at first day of the quarter, for example, or First Monday of the Quarter), than you need to update your script to check the Date every time the reload starts and proceed the reload only on desired day... In this case you can schedule a reload any way you want (even to start it every day) since it will be proceed by the script only at the specific date you've selected.
P.S. When applicable, please mark this answer Correct or Helpful.