Sorting results of ps by start time
You use etime. That's elapsed time, in days, hours, etc. which is suitable for sorting numerically. If it's the first column, I think ps will sort by it automatically.
Otherwise, you can override sort order by using --sort, but make sure it is after the -o option, example:
ps -o pid,user:32,start,etime,state,time,vsz,args --sort=etime