Hi,

I hope you are doing well.

Whichever books you are currently reading from, you can always continue doing that and try your best to understand their concepts completely.

I can’t answer if they would be completely enough for your preparation as I’m completely not aware about exam papers and information related to NTSE exam.

but,

Meanwhile, I’ll suggest you to have a look at the Below link which I would be sharing that will provide you the best books one should read while preparing for NTSE exam

https://school.careers360.com/articles/best-books-for-ntse

I hope the above information helps.
All the very best for your exam.