Ah, but your expectation should be for thoughts to intrude. Even the greatest meditators experience this and you should expect this to be especially true for you as a beginner.

Meditation is not actually about being free from thought. The goal of meditation is actually to notice when attention wanders, thoughts come walking in and pull back to the breath. That's the muscle you're strengthening. Each time you notice an intrusive thought, is actually a moment when you're actively meditating.