Questions about development of resin glands

I don't have any plants currently that are far enough along into flowering to start producing resin glands so I got to thinking... I've never really paid attention to the timing on when they initially start to produce the trichomes. So if anyone could answer me... what is a ballpark average time frame for when plants first begin production of resin glands? I'm guessing it varies from indicas to sativas, and currently my Sativa is the furthest along in flowering that I have so hopefully I can answer that one myself here soon. However, I'd love all the insight I can get on the subject.

If you can give me an average age range as far as # of weeks into flowering, and if there is a difference from indica to sativa or differences for whatever reasons. I just want an idea cuz I've never thought to pay attention before, and I have several plants that will soon be approaching that stage and I'm excited for that time to come.

Thanks ya'll!

Most of what I am finding online is not helping me much at all... and I am finding answers that I already know. Basically I just want to know when plants typically produce visible trichomes, my guess is that it is somewhere around week 5, on a plant that takes somewhere between 7-9 weeks to flower? And perhaps takes longer on plants that require 10-12 weeks of flowering? I don't know.. Hopefully some of you have plants in a wide variety of stages and can examine them and let me know. I really hate thinking of questions that I want answered and then not being able to find an answer to it online myself, which is why I enjoy all of ya'lls company so much haha. That and... I simply just love to look at pictures of bud. I could give up consuming cannabis if I had free access to smell/observe all of the best strains of marijuana anytime I wanted, looks/smell are my favorite part haha.

thx again fellas