Runner's Training Tips: Should I or shouldn't I???

So, long story... I started running and training competitively last September and was shooting for my first marathon as a sub 3:10 marathon in the NJ Marathon May 4th. I was going to run this with two of my friends who are shooting for a sub 4 hour marathon. I continued with my training over the winter, and being the Skiing/Snowboarding buff that I am headed into the mountains and managed to mess up my ankle the first weekend of January. I couldn't walk for about 3.5 weeks. I started trying to run again mid March and started with my training again 2 weeks ago. I ran a 1/2 marathon last weekend as an easy run which is currently the furthest that I have ever run, and did it in a very comfortable 1:45 and did the last 3.1 miles 30 sec below my target marathon pace. I know that I will not be able to do a sub 3:10 in two weeks, but I know that I should be able to complete it with little problems if I run with my friends. So... should I run it? or should I keep training and pick a marathon later in the year. And if I do run it how should I adjust my training, should I cut the distances of the other runs that week and the week after? Please keep in mind that the furthest I have ever run is the 13.1 I did this past week. I know my goal is in my reach if I continue my current path so I'm a little reluctant to stray and throw my training out of whack, but I think that it would be a good opportunity to test the waters and spend time with my friends.