Is it normal if looking through one pin hole made by the hand that the edges will be slightly blurry and dark, but the vision in the center is clear and better than without pinhole?

Yes, it is normal. The edges can be blurry due to diffraction of light at the edges. For healthy diet: http://www.choosemyplate.gov/., exercise 30 minutes/day, drink enough water daily so your urine is mostly colorless, have safe sex, no tobacco alcohol weed or street drugs. Get HPV, Flu and Covid vaccines. Wish you good health!

Yes, a pinhole reduces or removes all refractive error to typically central vision will appear more clear through a pinhole than without. If the difference is very significant, you should seek out an eye exam as you will likely benefit from glasses or contact lenses.