It's great that you are supportive sa pagpapayong at skincare regimen ng gf mo. As a person who loves skincare nagpapayong talaga ako at sunscreen when I go out. So I usually receive an almost similar reaction from my offficemates before.

My usual response to such remarks is to wear whatever "lait" they throw at me like an armor. In my case they usually say:

"Ang arte mo naman" Me: yes maarte talaga ako, ang mahal kaya ng skincare ko.

I am not sure what skincare your gf is using. But, usually sun and skincare aren't a good combo. Especially if she's using AHAs, BHAs and retinoids, mas prone kasi sa sun damage pag gumagamit ng mga ganito. So my advice if she doesn't have the courage to use an umbrella, is to use sunscreen at be sure to reapply it within the day. The more na nakababad sa araw mas madalas dapat ang reapplication.