Have a baby shower early or not at all?

I'm pregnant with what will be our first child. We just found out what we are having and I want everything purchased early so we are ready rather than waiting til last minute. I am a planner and I like having things done early so I don't have to stress about them. We talked to my mom and mil about it soon after we found out I was pregnant that we wanted an early baby shower or I would probably have already bought everything.

My mom offered to throw me a baby shower and she and mil were totally understanding of us wanting to have it early so we still had time to buy anything we needed after the shower and get everything organized/ready while I still felt good and had energy and without feeling rushed.... now my mom is looking to put off the baby shower until later in our pregnancy and it doesn't even look like she has begun planning nor set a date.

I'm really not trying to be ungrateful or anything, but we don't want to wait a long time to start buying so I'm thinking of telling her I don't want one if she insists on putting it off... I really want mine by 24-28 weeks at the latest so anything we need we can get from yard sales or store sales/clearance, rather than spending a LOT more on items because we waited to buy them and couldn't shop around...

Thoughts?