As an irrigator for 18 years, I would like to make some comments that may be helpful for you.
Firstly I suggest you look into getting some Imodium or similar to "harden" your output. I had the "loose" problem too after my operation. This will be a big help for you.
Secondly there is no hard and fast rule for ostomates who irrigate. Everyone is different and everyone's insides work differently. I wouldn't be aiming to irrigate every 48 hours. In reality it is more likely to be every 24 hours. (Because of a parastomal hernia I irrigate every 12 hours. It only takes half an hour and then a wonderful shower....God I love it)
Thirdly I do know that after treatment, your insides need time to settle down from the trauma of the surgery. It was over 12 months from my op. to when I started irrigating although I agree with you it is something I should have been told about before they started cutting. Don't start me on this subject!
Lastly, when you do begin irrigating, stick at it. It does take time to master and it can be very frustrating but if you persist you will not look back and you will be able to put a bit of tape over your stoma like I do everyday. No more bag!
I wish you the best of luck.
P.S. Remember irrigation does not work with illieostomy, only colostomy.