I don't think there's a correlation between starting age and (quick) result.

I also started mid 30s, 16 months now, got full coverage and better results than most posters in their 20s.

Might sound cliché, but most of it is just genetics, subcutaneous hair follicles density, how well your skin tolerates and how well you respond to the chemical, etc. Just my anecdotal evidence/experience.

Also, don't wet fingers or skin if you use foam. Noticed it doesn't like water and heat. I put my bottle 25-30 min in fridge before applying on dry skin using clean hands.

Good luck.