Drug Involvement and Inadvertant falsification due to immaturity and youth

I have recently (within the past week) applied for a TS/SCI security clearance and I have some worries that I hope you can help me with. I served in the Army national guard for 9 years, completed 2 deployments, received numerous decorations, and received an honorable discharge after completing my service last March. During this time I was asked to fill out three different sf86 questionnaires for a secret clearance, the last one being in 2010 orearly 2011. I was never actually granted a clearance because our admin personnel never turned in the paper work on time. I was young (20-23) and careless anddid not list any drug involvement in any of these forms (you can actually view these forms and see that I did not seem to take them seriously, a real sign of immaturity). In my most recent application (I am now 27), I put more thought into my past and tried to be as specific as possible about these instances. This led me to list some instances that I honestly did not feel were problems until I think back on them now. In 2007, while throwing up in the bathroom of a bar from having a few too many drinks, an old high school acquaintance (whom I do not associate myself with) found me and told me to take a white powdery substance… insisting it would make me feel better. After taking it he told me it was cocaine. This was a one time instance and for the longest time I thought it was a joke since I did not notice any of the commonly associated effects of this drug, and nothing ever showed up on a drug test I had to take later that month. This is why I did not list this instance on any application until now. Also, In 2010, I used a form of Adderall to help me study. This drug was given to me by a friend and I thought I was using it for the right reasons because I believed I was having a concentration issue. I used the drug maybe 5-6 times and I whole heartedly did not believe I was abusing this drug. Now I realize that I was abusing it because it wasn’t prescribed to me. I have zero other drug related instances to report, and I was never trying to deliberately fool the system. I was just negligent. This is why I decided to list these issues now, because I did not want to intentionally or unintentionally hide anything that is on my conscience.

My question is this: Do I even stand a chance? Consider I was young, and since my last application had another combat deployment to help me grow up and was awarded an engineering degree. Also consider that I voluntarily listed this information, knowing that it would hurt my chances but showing my increase in maturity. Should I wait to see if I get denied a clearance or should I play it safe, turn down the job, and have the clearance halted to let some more time pass? I have recently graduated as an Aerospace Engineer, and being denied a clearance can drastically effect my employment opportunities.

Thank you for your time and replies.