So do I! I started when I was about 11 (I'm now 36), coinciding with moving away from my home town for my dad's work - I was distraught at the time, though I settled well after a year or so and now love the place we moved to. It may not be anything to do with that of course - 11 is the prime age for it to start.
I've had a lot of CBT which I have found helpful-ish at the time and have stopped pulling for a while in the past, but always go back to it when something stressful happens (and then it takes years for me to try to stop again).
I have a ritual - forage to find a 'good' hair (thick or crinkly), pull, bite the root, run the hair through my teeth, discard. If I'm stopped during the ritual it feels horrible.
I've gone grey in the parts I pull from much more than the rest of my head, and the top of my scalp is damaged and the hair thinner than the rest. Fortunately I have thick hair and generally get away with it, but I'm very aware of my thin patches. I used to keep it very secret, but as I've got older I've told people and everyone has been surprised but very nice about it.
Most of the time I actually like doing it and don't want to stop. I know it harms my appearance and probably isn't good for my insides either, but it calms my anxiety and feels good. I enjoy finding good hairs, it's a nice perk in my day. I definitely do it more when I'm on my own and not physically active - so when reading, watching TV or working. If I spend a day out and about with friends I probably won't pull at all.