If this is your first sewing project of this type, you have done a superb job. The kilt looks excellent. You are fortunate to be thin. I hope the kilt will be with you for a long time to come. My nickname in school was Dixon #2, as in the school issued pencils... At 6'1", I had a 25" waist. I also wore a kilt to school.
Congratulations and enjoy the admiration when you wear it. Your craftsmanship will show.
Slainte