Should I be preparing my child for 11+ in Year 1?

In Year 1 parents should ensure that their child is achieving the expected levels of the National Curriculum. If their child is doing this & school can confirm so then the parent should aim to get their child ahead within the National Curriculum. All the objectives can be found online.

Simply preparing for a test in the distant future with no acknowledgement of current progress be futile.

https://www.gov.uk/government/publications/national-curriculum-in-england-mathematics-programmes-of-study/national-curriculum-in-england-mathematics-programmes-of-study

https://www.gov.uk/government/publications/national-curriculum-in-england-english-programmes-of-study/national-curriculum-in-england-english-programmes-of-study#key-stage-1—year-1