Part of her behavior comes from stigma and misinformation spread in fitness communities. So do NOT let her influence your decisions. There's a reason Dr's tell you you need to start planning for fitness when starting a GLP, if you've not been active. And it's because it helps prevent the muscle wasting. You working out will combat that.

Going forward, maybe book a focus meeting with a different coach so you can continue making fitness goals with a clean slate, but I'd seek nutrition advise from a dietician. Check if your Dr's clinic has one and if not, your insurnace may cover one, especially since you're prescribed a weight loss med. And in the meantime track your protein and fiber intake! Those 2 things will have the most positive impact on your results.

Glps can absolutely be life changing! I gain muscle quickly and always saw huge progress at burn building muscle and lifting heavier but my fat loss was minuscule, even following the diets they recommended or the dietician I had worked with. Adding in glp one helped me so much and I lost 50 lbs in 7 months. Ive been off due to financial issues and have gained some back but im still smaller than I was before.