Question: Am I not supposed to cut my hair or trim my nails during the first ten days of Zul Hijjah?
Answer: Yes, the one who is going to be doing Qurbani of his animal should not trim or cut his hair until he completes his Qurbani. If he did not cut his nails etc for forty days prior to Zul Hijjah, and the 40 days will fall in the first ten days, he must then cut his nails and hair. Leaving it to grow for more than forty days is sinful.
Saturday the 10th July 2021, nails and hair should be trimmed