DSW with scheduled race

I looked around and haven't been able to find the answer to this question. I have trained myself up to running about 6.5 miles 3 times a week over the past year and a half.  I decided to do the DSW recently to maintain general fitness and keep my conditioning up and i am liking the suggestions. I have decided to run my first 5k in July and added the race to my calendar with a goal time of 25 minutes.  I know it will adjust my DSW based on this event but am concerned that it will not train me to keep my current conditioning. I have worked too hard to lose the conditioning i have built up and am worried this is what will happen.  Am I better off deleting the event and just doing the DSW based on my personal metrics and distance or will it keep me at my current level even with the 5k race on the calendar. Any help is appreciated, thank you!