Is AST always supposed to be lower than alt? Both of my values are always around AST 24/ ALT 18. Doctors never mentioned wrong ratio. I am 59 yo female, excellent health, workout 6 days/week.

No. No clinical relevance of the ratio when the liver enzymes are normal. Alt of 19 for woman and 29 for man. For patients with chronic liver disease if ast/ alt >1.2 --- it is indicative of advanced fibrosis.
No worries... The alt and ast, also known as SGPT and SGOT are liver enzymes commonly assessed in metabolic lab panels. The normal values are generally less than 40 or 50 depending on the lab control. Your labs are normal and the ratio only matters when there is enzyme elevation. Various toxins or infections are associated with different patterns of enzyme elevation. In your case they are nice and normal.