AITA for telling my girlfriend I won’t propose until she gets back healthy ?

I 24(m) and my girlfriend also 24 have been together since high school. Think of as your typical high school sweethearts. Basketball player and cheerleader etc. After we both graduated college we moved together and have been living peacefully. However she is not as active as she once was and gained some weight. Nothing to much roughly 30 or so lbs. I still find her extremely attractive but, I just worry about the future and, our health. Since she graduated I do know her job is very demanding and she doesn’t have that much spare time to work out. Recently I have been trying to encourage her to work out (sometimes with me) but she is always pushing back. We have recently been talking about marriage lately and I told her, I would postpone proposing until we make some better life choices. I understand she is fine now but, I’m scared to lose her 20-30 years from now due to health complications. After explaining my piece she didn’t say anything she just got up and went to the bedroom. I waited about 10 minutes and decided to check on her. The door was locked but I could hear I sniffing. I asked if we could talk and she said no. I told her I still want to marry her and that thought never left my mind. She then told me if I can’t accept her for who she is now I don’t deserve her when she is at her best. She told me she knows she gained weight she just thought it was“Happy Weight“ as she likes to put it . And she didn’t think I felt that way about her weight. I told her the weight is not what’s bothering me just how she stopped caring about her health since she stopped cheering in college. I apologized because, I genuinely did not want to make her cry. It even choked me up to hear it. We exchanged some more words before she packed her a suitcase and left. It’s been 3 days and, I have been calling her constantly. I just recently found out she has been staying with her sister because, her sister finally picked up for her and, tore me a new one. Her sister and I have always been on good terms because, my older sister and my girlfriend’s older sister are best friends. Which how we actually ended up together. It felt horrible to hear the words she was saying to me. Not only that I knew my sister had to already know because, they tell each other everything. So I called my sister and she was as equally pissed. She told me she would except that behavior from our younger brother but not me. I’m just so lost right now and I want her to come home. I feel like an Ahole but, I genuinely just cared about her and us for the long run. AITA?

Update

Wow! I did not expect this post to blow up the way it did but here we are. Anyway we talked about over lunch and, she is coming home. After seeing my post on reddit. She was taken back at some of the post, others however were helpful to both of us. Despite what some people may think she knows where my heart is considering my past. I did not feel the need to explain this but in middle school I was the tall pre diabetic fat kid. By 8th grade I had completely dropped my weight and I started playing basketball in high school. So I would never fat shame her. As I once said she looks fine. But for everyone to keep saying it’s only “30” lbs it’s true. But that is 15lbs every year since we graduated . If you multiply that by 6 or so years that is 90lbs. And she is only 5’1. The thing is she is used to eating her high calorie foods and snacking and being able to burn it off easily. I can tell it makes her uncomfortable and she doesn’t like it. Why? Because she was the one who told me she gained 30lbs and seemed disappointed. I also think some of you missed the point of me offering to do it with her. I genuinely do care solely on her health. However if It was just based on looks which is not, I still don’t think there is anything wrong with wanting your partner to always look their best. Especially when you know they can. She understood all of this and was only upset with the marriage part. Which I did agree was a sh*t move and insensitive. And told her I would not make it a big deal what she looks like. But she did agree to watch her calories because, did acknowledge she eats/ snacks as if she still works out constantly. So agree I was the Ahole to a certain extent. But I think some of you, (Not all of you) are clouded by your own personal judgments or experiences and projecting without really knowing me. What ever happened to being innocent until being proven guilty or the lack of giving people the benefit of the doubt? She knows my heart and that’s all that matters.