MD Helpppp Advice caught smoking

So my freshman year I was caught on a weekend smoking with a couple of my friends marijuana. It was a dumb immature mistake. I was not put on probation just had to write a essay of why marijuana is bad. I feel dumb now that this is catching up to me. What are my chances that this will effect me solely from receiving an interview or acceptance? will they just throw my application away? It was not my marijuana but I did admit to smoking. I have never been caught since or before, I volunteer at local elementary school as well at basketball camps. Is this a major issue I should worry about when applying to MD programs?

Has anyone gone through a similar situation?

Thanks for the help and advice.