AIO. My (new) bf wants to replace all of my bras, underwear and lingerie.

I need advice on this asap. I’m 18 and my bf is 19 and we recently just got into this relationship together. He said this to me today and I’m not sure what to think. Is this a red flag and should I run or am i overreacting?? The lingerie part I sort of understand but bras and underwear????