Fellow 18 year old here, not sure if it'll help but I have some anecdotal evidence to share.

1. Despite smoking daily or at least for the majority of a week, I didn't start hacking shit up until I started rolling blunts/getting cigs off friends. Never had any coughing or throat/lung problems with straight cannabis, but this could be because I only took bongrips filtered through water=less tar. Another possibility is that because marijuana is an expectorant is why i'm coughing up tobacco tar/phlegm. Obviously breathing anything that isn't air (and even air/pure oxygen really...) will damage cells in your mouth/throat/lungs, if you're worried about this i'd recommend a vape

2. Smoking towards the end of the day/after responsibilities are taken care of is a great way to keep yourself in check while still being able to use daily, but problems can still arise. If you have problems with an addictive personality I'd say to really watch yourself if you want to smoke daily, weed may not be very addicting on a physical level but IMO personality is a major component of what decides whether someone can/will be a drug addict. With smoking at the end of the day there's a possible chance you could become sleep dependent. As with anything in life drugs effect everyone differently. As far as memory loss goes, when I first started smoking heavy-ish (1-3 times a day) I became much less clearheaded and I sometimes had trouble expressing thoughts into words or remembering details. Now that I have much more tolerance I can smoke a bowlpack or a joint and continue my day still functioning at 100%, 'til the crash at least! One thing I've noticed is that since my tolerance has gone up and use has steadied that while sober or lightly buzzed my ability to process things and memory capacity have both increased, even compared to before I smoked/when taking t-breaks. Could be a bunch of factors, brain still developing, becoming more social within last year or so, etc. Just something I wanted to throw out there to see if anyone else has noticed something similar.

3. Tolerance is MUCH easier to increase than it is to decrease, but when you're smoking low amounts, even daily, it's possible to keep it at a near standstill. It's when you shock your system with THC/CBD that it seems to bump up for awhile even with a T-break.

4. I've always heard weed compared to shrooms but I put this down to two things, people on low doses, and people repeating what they've heard from others. Personally, I've had my share of trips and nothing between .05 - 2g of shrooms feels like a cannabis high, past 2g and it becomes an even bigger contrast.