I come from a long maternal tradition of excelent/professional/sewers/dressmakers. I am a bad sewer, I have dyspraxia, but I enjoy sewing and still do it. DD started sewing at 4 and hasn't stopped since. Her house looks like one of those Kirsty Allsopp home crafts tv programmes.
DD and I decided that DGD should learn to sew, so at about 4, when she came to visit, she made a skirt for one of her dolls, on her next visit, several months later, we used exactly the same technique to help her make a skirt for herself. This included a trip to the fabric shop to buy the fabric - and it hasn't really stopped since then.
Att 11 we all clubbed together to buy her own sewing machine, and now she uses it as and when she needs it to to alter clothes, repair clothes and refashion clothes.
She is now 18, and may not use her machine for 6 months at a time, but then will make or alter something. The main thing is that she has the skills and she has the equipment and those will last her a lifetime.
We tried to itnerest my DGS in sewing, but he showed little interest.
I think if you are to interest children in sewing they learn best through making things. DGD picked the basics up - sewing buttons, turnimg hems etc when we made clothes that required them.