you truly are a fucking spaz.
check engine lights don't turn on when you need an oil change...
Yup... check engine light will not come on if you need an oil change. Make sure your mechanic has the equipment to see what codes the engine is throwing.
If you meant the maintenance required light... then thats a different story. Those come on every 7.5k miles as a reminder to idiots to service their car. That can be reset with no tools.