Lookup the First Positive Value
The following formula returns the first positive value from A2:A10...
=INDEX(A2:A10,MATCH(TRUE,A2:A10>0,0))
Note that the formula needs to be confirmed with CONTROL+SHIFT+ENTER. If done correctly, Excel will automatically place curly braces {...} around the formula.
Based on the sample data, the formula returns 12.
Sample Workbook: Download