Is a caution for possession of a controlled substance a problem for me?

I got a caution for possession of a controlled substance two and a half years ago; I’m 39 with no previous convictions or cautions married with 2 children. The situation was a nightmare I was out at Christmas on a works do with people I didn’t know many others were handing around small packages which I umed were drugs (not being totally naive) as the night went on along with lots to drink I was handed one of these packets which I put in my pocket and forgot about , I wasn’t sure what it was and had no plans to take it as I’d never done before just didn’t want to look a fool how ironic, anyway when we walked into the next pub there was a police officer at the door who took me into another room and placed my hand on some sort of scanner, I now know this was a drug testing machine and to my surprise showed up positive, got searched and he found this packed in my pocket which turned out to be cocaine I had never taken anything like this and was totally devastated, at this point the officer advised me to accept a caution and attend my local police station in the morning which I did. The problem I have is I was hoping to become a college lecturer but am unsure now if it is worth me pursuing this career or just give it up?