Wow, i can relate to this as well.
Its so interesting to me that our families still feel that its okay to critique our bodies as adults, and make comments that would get them some major attitude from any non-family types out there.
How frustrating is it to get to a point where we start to feel really great about the results of all those hard hours in the gym, all those damned yams and tuna and myoplex shakes etc. and LOVE how strong we look, only to get these type of comments from family, friends etc. about getting TOO big, TOO 'masculine' (read: upper body definition and mass), TOO cut etc. There is so much fear out there about what women SHOULD be like, how our bodies need to conform to a set of "feminine" ideals etc.
Look at how people rip into Madonna when she gained all that muscle mass from "yoga" (i suspect there may be other influences here as well, but, more power to her) . It just goes to show that a physically powerful woman is still a huge threat to a lot of people out there. Im so happy to be at apoint in my life age-wise (30s) and physique-wise that i see this kind of behavior for what it is (fear and jealousy) and take huge pride in how I look. Self acceptance is a long bumpy road for so many of us: don't let anyone bust your high when you get there!