Question about MEPS and SECRET clearance?

I'm 20 years old and I signed with the Navy back in November. The job I want requires a Secret security clearance and I think I made a mistake at MEPS on my papers. I tried Marijauna when I was a 15 like 2 times but I never became a pot head like most people did because I didnt like the feeling of it and when I was at meps i got confused caused it said list the drugs you have taken since the age of 16 our last 7 years. And I put no to it and put no to druge usage. What should I do. Should I tell my recruiter I don't ship out until July. What will happen to me if I tell them the truth. Will I be kicked out of DEP?