Want to start playing dragon quest xD

Hello I wanna start playing the dragon quest series (DS) but I'm unsure of which one I should start with.

Probably V.

yup Vyou should probally try joker too

If you mean the main series you can start with either V or IV, you won't miss out on any story related stuff if you start with DQV just so you'd know.
One tip I can give u for DQ5 is to not buy equipment once you reach a new town, instead save your cash and buy equipment in the NEXT town.