I should be starting T soon and I was wondering how quickly those of you on testosterone have lost the body fat in hips/thighs. I'm really asking those who work out regularly. Could I possibly see any results after three weeks or so?

I would have to agree with above. I was fortunate in that I had very little fat on my midsection. I think the best thing to do is lose general weight and try and get you upper body wider. This will take the focus off the hips. You can gain muscle pretty quickly on T.
Myles
1 year on T this week!

I've will have been on T for 3 months next week and have some fat redistribution already but that really just started showing up the last month definitely not at 3 weeks and I was working out pretty regularly those first couple weeks. I had very little fat. I weighed about 100 pre-T and was 5'2". I have gained 10 pounds and am an inch taller(whether I stand taller or actually grew is debatable but I don't care either way) but have gone down a pant size(29x30 to 28x30(or at least I would if I felt like buying new pants)).

Carson if you're under say age 22 or 23 you may still be growing, I put on an inch in the Army and I can't blame it all on the great food (the food really was good).

I just noticed one day that I'd lost a lot of fat around my hips and that these "side muscles" were standing out. Like they do on bio-guys. Me happy.

Yeah I'm under 22. I'm really not bothered by my height at all even though I am still only 5'3" but I would be happy for an extra inch or two.

Took me between three and four months, with cardio 3x a week and weights 3-4x a week.  Woke up one morning and my hips were gone, it seems to happen really fast when it does eventually happen