I'm definitely going to agree that delaying transition is probably almost always going to lead to regret. I'm another one that has regrets.
I've known that I was experiencing intense trans thoughts since I was at least 15. But being the pigheaded teenager that I was, I let myself constantly be convinced "no one would understand," and so I bottled it up. I had a chance to transition at 17 when my mom discovered my diary under my bed while she was cleaning one day, read it, and was shocked to read all of the horrible entries about how much I hated my gender in it. She confronted me about it, on the very same day that we were going to my therapist's office. (She sent me there, because she knew that something was wrong... she knew that I was struggling in school, didn't have as many friends as I used to, and seemed depressed, withdrawn, and angry all the time.) I had a chance to admit it then. But I made the decision to not admit it. I explained the journal entries away as just being a sexual fetish.
You know what that decision cost me? Another TEN years of feeling like complete s***. I barely passed high school. I failed out of my first college, and was within one semester of failing out of my second one. Even when I finally started getting it together, I became terribly withdrawn. I had no friends anymore. I'd completely forgotten how to talk to people and relate to them at the most basic of levels. My mind was still constantly at war with my body, at war with my sex-drive, and life was basically just a constant unending battle to perform the simplest of tasks that most people were able to do without even thinking about them.
While I don't think my HRT results would have been that much better, I missed out on pretty much my entire young life. High school and college is usually the best time of a young person's life, when they're still young and wild and free, and living it up. I'll never have that experience, because due to not confronting my trans desires, I wasted my entire early-adulthood buried in a mire self-hatred that made it impossible for me to function both socially and professionally on the most basic of levels.