NO you are not to late
sow in modules you will find that cabbage plantd in september will need one or two hoeings before winter sets in this stops the weeds out growing the plants, in march top dress with 50g of nitrate of soda and when the bed is cleared by mid to late june why not sow lettuce or carrot in the bed

Depends on which cabbage you are referring to.. if you looking at sowing spring cabbage or next year then no.