You will hear many, many women over thirty say that their eyebrows are sparser than they were when they are younger, and blame this on their past “overplucking” habits. (They usually also talk about this like it’s some kind of totally nonsensical obsolete ritual, even as they continue to get their brows threaded into the shape that is presently socially acceptable!)
I worry that people with trich will get stressed about this, and I want you to know that they aren’t exactly right. Their eyebrows are getting sparser (thinner, lighter, changing color completely, changing texture) because they are aging. This happens to everyone, regardless of what they do to their bodies in their twenties or whatever. Most of what they are describing is regular aging! You are not permanently, irreparably damaging yourself. You are not doing something that is going to ruin you for the rest of your life.
Trich might contribute to a faster appearance of aging in the way that I mentioned before, which is essentially speeding up the individual growth cycles of follicles and maybe speeding up their life cycle, but these kind of cycles are super under-researched and this isn’t fully scientifically confirmed, even though I’m guessing there’s a lot of money in this cosmetic research right now. The important thing is that your skin doesn’t say, like, “we will produce exactly 1000 hairs from this spot in our lifetime,” and trich isn’t hurling you toward this kind of follicle death. Eyebrow aging and growth is contributed to by a million factors, just like the rest of you. And eyebrow thinning likely has more to do with how your facial skin ages than anything else.
The bottom line is: this thing you are struggling with is not going to ruin you forever cosmetically, and everybody ages. :)