I started a couple months before my 29th birthday and I think I turned out pretty well. I noticed a decrease of strength pretty quickly, and the muscle started coming off at around 2 months, but I didn't start having a feminine muscle tone til about a year in. A lack of testosterone should be enough to melt it off. As far as body hair ... I still have an unacceptable amount at nearly 1.5 years in. It's thinned out and become much finer, but I still need to shave pretty much everything.
I wear a 34B, bordering a C. Pre HRT my band size would've been a 38. I used to have running back thighs, now they're flabby. Men are always checking out my butt if you ask my roommate. Last night, he brought home a guy that said he didn't know I was trans, even though I was wearing no makeup and still have fairly noticeable facial hair. I honestly get that quite a bit... with just light makeup, most of the time if somebody learns that I'm trans, they're in shock. My cheeks are filling in quite nicely, my skin is definitely female in texture and tone, my body odor is completely female, my genitals don't even smell at all anymore, I don't need deodorant unless it's hot out... all that and everything about me screamed male pre HRT.
I will say sometimes I look in the mirror and I'm not COMPLETELY satisfied, especially when I have no makeup on. However those are bone issues (mandible, nose, chin) that can only be changed in minor ways through HRT. Passing is no problem whatsoever with me. I don't think being 30 is going to hurt you much.