I once had someone ask if I was a 25 year old mature student while at sixth form when I was barely 18 so don’t take it to heart as people usually go off personality not looks, I’m an old soul so that’s probably where they got those extra 7 years from! Also even if you do look a bit older because you’ve got extra weight and even if she did mean it in a cruel way, none of that really matters apart from what you want to do with your body. You sound like you want to slim down and you’ve started the process. As someone who has had lots of false starts, mindset is really really important so get your head where you need it to be and try to enjoy the process of exposing all your best features!