No, you shouldn't need to use all of your starter. Once the starter has peaked (i.e., risen as high as it is going to go and maybe is starting to recede a little bit from the high water mark), measure out the starter you need for your dough into your mixing bowl. Before adding the water, flour, or salt, make sure you have at least 20 grams of starter leftover in whatever container you typically feed your starter in. You should have enough starter left to feed with flour and water as normal. If not, it's okay to use a little less active starter in this recipe than what is called for.