Q) How long does Breast development take?
I have heard that it can go for years.
Q) Will the size of my breasts be random, or will it be determined by the dosage of Hormones?
I have not heard about extra dosage having effect on that, but the most tricky part is to figure out Your most optimal personal dosage, which takes some tweaking by Your endo.
Q) Will my Breasts be sensitive or numb?
Pretty much like those had by any cis-girl

Which means - QUITE sensitive.
Q) is taking hormones likely to cause me to be aroused by men?
Maybe, maybe not. Estrogen for sure has its impact on brain - the idea of being with a man before the HRT pretty much disgusted me (I had those fantasies when I was teen, but I never had male body in them). Now... I am not sure. I still find women to be hot and cute, but when I am in the presence of men, whom I find attractive I kinda start getting unusual ideas and thoughts

. The most disturbing is that my behaviour changes into something playfully seductive. I just have to do it and I cant resist. By the way, that absolutely does not mean that I want to have sex with them or feel aroused (in male sense) - actually, the whole concept of arousal changes a lot too. It shifts towards the feminine, which means slower, less visual but more mental and emotional.
Q) Will I take on any feminine personality changes.
The same as the previous one. Besides, what is male and what is female personality? it is 21st century and girls can do pretty much the same stuff what guys do now - and quite often we do those things better than they

.