You are using the rocks to date the rocks that is what you are saying above.
No. Igneous rocks can be dated very accurately using multiple independent radiometric clocks.
Your silly Mount St Helens nonsense has been explained to you many times but you prefer to listen to buffoons like Ken Ham, Kent Hovind and Duan Gish.
If we want to date a fossil - fossils are found in sedimentary rock layers - all that is required is to date the igneous layer above it.
Read Wien's article. It was written especially for YEC christians like you. It does contain some big words but if you ask very politely we will help you.