Patient I had just admitted was ordered heparin subcutaneous every 12 hours. I gave the first dose upon admission and then the next morning ended up giving the next dose 6 hours after that first dose instead of 12 hours after the first dose. The computer didn't automatically reschedule the medication for 12 hours after the first dose and scheduled the next dose for 6 hours later. After I realized I adjusted the doses afterwards to be every 12 hours. I am new nurse and my preceptor wasn't concerned about it. It's bothering me because I feel as if I made an error. Would this really be considered a big deal?