At age 27 you should have had the glasses refraction don after your eyes were dilated, called a post cyclopegic refraction. If it was done without dilation it is possible that the new stronger sphere (-6.00) may be due to what is called 'pseudo-myopia due to accommodation" If your glasses RX was done that way then yes you could have gonne 3 diopters more myopic. However at age 27 it is unusual to have a 3 diopter increase from age 22 to agd 27.