Hey , was wondering what is a good time in to the game to start doing Dragon 20 or im already behind ??

im 30 days in , got high kathum today and some other epics from the ancient event ( no legendery on account ) 

Im F2p got 4  lvl 60s , 3 with full mastery .. working on my next 60 to get dragon 20 (Artifacts looking very bad - didnt do mutch artifact farming yet mostly leveling )

Im on Stage 18 Dragon  under 3 min - 2:30  and i probaly try to get myctical orn priest 60 cuz my kael accuracy is bad and doesnt apply poisen in that stage (i cant regear him yet ) and i dont have other hard hitters/poiseners/or  enemy hp hit champs  

also its my first account , didnt know anything when i started (and also started without a promolink xd ) 

orn  is on 210+ accuracy with perception/regen gear (not the best gear tho ) looking to booking him too mayb.

my 60s (kael,deacon armstong,apothecary, peydma) can this team with orn priest beat dragon 20 ?

is stage 18 and 4 lvl 60  ok for a 30 day account ? or im behind ? and is orn priest a good champ for dragon 20 ?