EDIT: Also, in almost all clearance paperwork you only report back to age 18. So if you're a recent graduate (what this seems to be for) at around age 22-23, and you stopped after high school you likely wouldn't have to report anything at all.
Years ago the rule of thumb was that they'd give you a clearance if it'd been 1 year since you used marijuana and 3 years since you used hallucinogens so long as you'd demonstrated a commitment to a drug-free lifestyle since. Anything serious like opioids or alcoholism would require you to have gone to rehab and seriously reformed your life.
In more recent times they seem to have gotten more lenient regarding recent marijuana usage, but I've been out of the industry for a minute so I can't say for sure. What I've always told people is that if you want a cleared job and have done drugs then 1) tell the truth, and if that would get your clearance application denied then 2) wait until it's been long enough so that it won't and clean your act up in the meantime.
Note that despite how important it sounds, "secret" is not a very high clearance at all. It is the actual lowest classified status - there is "public trust" below that (eg for cops/etc) but that's not an actual classified standard, and FOUO/confidential/etc are not actual classification levels either, just handling guidelines.
Any time you are working on anything military-related you will probably need secret clearance at least. Anyone working with even a basic level of knowledge of military technical or operational capability, or force strength/moment/etc, will be at least Secret.
Anything that you think of as actually being deserving of "secret" most likely falls into the "top secret" category, "secret" is just the completely banal stuff, and you don't have to go far to bump into TS/SCI positions in STEM fields doing military contracting. Any sort of advanced research or development work is probably at least TS if not TS/SCI.
Actual low-level enlisted don't need to be secret (notionally you don't need to know that stuff to "go there and shoot him") but all officers are cleared secret, for example, and I would guess probably NCOs as well (so there's a cap on how high you could be in the military without it). And basically everyone in the civilian world who interacts with the military will be secret.
When both the FBI and NSA came to my college they basically said that during a recruiting meeting and most of the students just left
T*ump made that federally legal with the farm bill. Some states have banned it.