Old but new dress

I've posted on here before about questioning my dress and if I picked the right one. Not asking that again lol Long story short, I had bought a dress when I was young and dumb and engaged to the wrong person. When I went to find a dress, I didn't like one of the ones that the gentleman helping me had given me so I tried it on last. It was perfect. It was my fairytale, dreams do come true, love it to the moon and back dress. I've never actually worn it, (besides trying it on) and I've never gotten rid of it. But about 15 years and a lot of weight later, it doesn't fit. Would it be wrong to alter and wear that dress instead? I bought it at a time where my high school boyfriend and I just started talking about maybe getting married (again, young, dumb, AND impatient lol) but I never wore it for him. Heck I was still paying it off after we broke up. I couldn't give it up. Thoughts? I asked my FH and he just asked if I had ever worn it to get married in before. When I said no, he didn't seem to mind. I do want to see if I can get the sleeves removed and shorten the train (Is that even possible??)