Pumping for Multiples

So my twins will be 15 months on the 17th. My supply recently took a huge hit because my cycle came on in the middle of a cold as well. So I told my husband we can introduce a small amount of cows milk when they make it to 15 months. I'm super sad about it and worried they won't like it but I'm also gonna be sad if they like it more than mine. Wish me luck.