1.5 years minoxidil, finasteride and microneedling

I started minoxidil at 18, then added finasteride and then added microneedling. I got my hair back.  What should I do now?

You can cut back on the microneedling to once a month. Keep up the other medication. It is likely that at 18, when you started this routine, you might have had good results from finasteride alone. 18-year-old men are generally very responsive to finasteride in the frontal hairline.