That is super cool it has your birthday.
That is so great you have the machine. Your story is almost like mine. I learned to sew on my mother's machine, also the 15-91, and I sewed on it until I got married. My older sister sewed a little bit on it, but mostly it was my mom and I that sewed for my sisters. (My oldest sister hated to sew - she just could not get into it. My other sister sews more now but in high school she was too busy - she was in band and debate club.) I was visiting my parents and somehow we got on the subject of the sewing machine, they were thinking about getting it out of the TV room it sat in since my mom didn't sew anymore. I said, Whatever you do don't get rid of it, of all the items in their house I wanted was that sewing machine. So my mom said, go ahead and take it now, and I did. I had driven up to WA that trip, we put it in the back seat and has been with me since. My daughters don't sew, but I do believe my youngest will keep it when I am gone. I can't worry about that. But I have it and I love it.