At 3 months of HRT I wans't getting proper erections.
Basically, if you can't get a erection long enough to have intercourse, you have erectile dysfunction, what seens my case. These days (6 months) it only goes turgid and never goes up. Way back, it used to hurt to have a erection, then the pain subdued and I haven't had full erections since then.
It varies from person to person.