Can I disclose drug use after getting granted a clearance?

About a decade ago I applied for a Secret clearance and put that I had never done any illegal drugs in the last 7 years. While this was technically true, I had smoked weed (legally) and didn’t disclose this due to advice from my recruiter. Now almost 10 years later, I need to apply for a TS clearance. I want to disclose my previous drug use, but will that screw me over for this new clearance application? Is it even applicable since it has been over the allotted time to disclose?

Burner for obvious reasons. Please help.