For the first time, you did fine. I feel you would have had better results if you used warmer water (like 103 deg.). The warmer water is easier to retain. When you get the "full" feeling, you should stop the flow and wait for the "full" feeling to subside, then resume the flow, repeating until your get the "no more room in here for another ounce" feeling. At this point stop the flow and relax. Try to retain the enema for 5 - 10 minutes and then expell. Take your time.
I have found that the single most important step is to fill the entire colon, whatever size your colon is. Your ability to hold more enema water will increase with experience. The normal colon can take more than 2 quarts to fill properly. An enema between 2 and 3 quarts will probably be a good fill for you. Some people can take 4 quarts, and a very few a bit over that. Do not force anything. Remember, it is not a contest.
If you are not able to obtain good results from one enema, you can repeat the procedure again. The second enema will often fill you much better than the first. I would not go beyond three enemas in one session. Your body will usually remind you when you have had enough, so stop there. If you still have not achieved good results, try another day. Good luck!