Veritas, oh my word!! That's the 1st thing that comes to mind after reading your latest post. I literally sounds like none of your family is supporting you, either in your sexuality or your weightloss progress. What the heck! they are walking all over you, I know you know this. I have to respectfully try to encourage you to STAND UP for yourself more. Next time, give your mom 10minutes to get her first load of laundry in, if it's not in then start yours...snooze you lose type of thing!
As far as your mom saying those things about what you could or couldn't get down to weight wise....well I don't know your body frame so it's hard for me to judge or guide you to a healthy weight. I know you haven't physically begun your transition, but I'll give you some hopefully healthy hints either way. My mom is a doctor and in her office she has these guides to health. For men they should strive to have a waist size of 36" or less for optimal health. And for women 28" however I read in a nutritional text once that for women a healthy weight is take the number of inches you are over 5' tall and multiply that by 5 then add that to 100lbs. This is what a woman 'should weigh' plus or minus 10lbs based on whether you are small, medium or large framed. With that said EVERYONE comes in different shapes and sizes. I think what you should strive for is to be healthy by eating a balanced diet and workout 5 times a week. As long as you feel good physically than your weight or shape really doesn't matter in my opinion. I can tell you that if you do in fact have broad shoulders, I'm picturing along the lines of football player broad, a medium may or may not be in your future just because of bone structure. You could use a bmi calculator but I dislike them because they don't take into account muscle mass. My ex husband was 6'2 and he weighed 210 (he played football in college) and was all muscle however bmi calculators always said he was overweight. My point is, lose weight to feel good for you, but don't set a certain size goal. Also don't let your mom discourage you, she's your parent and should be encouraging your new healthy lifestyle.
Your uncle, omg...give me his address and I'll punch him for you

his ridicule and 'teasing' is NOt okay. In fact it's harassment. Do you live in a house with him too? Personally i'd tell him to get his lazy behind off the coach and take a walk. Does he have a wife/girlfriend because with his hostile attitude I wouldn't be surprised if he ended up alone.
Your grandparents..all I can say is they're old and older generations while it's sad, they just are old school and I think it's too much for them to handle. My best friend before she transitioned last year lived as a gay man. Hee came out when we were in high school, and even tho he lived with my family, my grandma refused to even come to our home once he moved in & he was not allowed in hers. It was really sad especially during holidays because for those years she stopped coming to xmas, but what she was doing was wrong. Before my friend came out as gay, she loved him, she watched us both when we were babies and picked us up after school. He was like another grandchild. I'm sorry you think you may lose your grandparents with this, but you can't hold yourself back for them or anyone else.
I swear Jeremy, if you don't do this for yourself and think of you, you will regret it because it won't go away. I don't want you to resent yourself later because you didn't start transitioning just because of your family. You'll resent them, yourself and just be an unhappy person.
Okay, I didn't mean to write so much, but you are in my thoughts. Please, please, please stop letting your family use you, you're the only one that can stop it. If you let them, they'll use you to your dying day. I'm glad you're saving to get out of there, just keep taking small steps!