I'm not sure I understand the issue here.
How exactly are your kids' egos getting wrecked? Unfortunately, in life, not everyone is going to like you. They do have friends though.
The students at my kids' school...
I take a basket or cloth bag with our food and a small back pack with a change of clothes for the toddler. I can usually see our stuff so I don't cart it along with me. My phone and keys are in my pocket, purse is left in the car.
Advice from strangers: just nod and smile
Advice from family: just say "This works for us"
I don't think it has anything to do with Mom's age. I had kids at 27, 29 and 30 and got (and still get) tons of well meaning advice...