No one can tell you.
It would be better to ask the water temp, but you would need the experience to know what to do next.
You are about to get many recomendations, but without knowing your dive schedule, your timing of repetetive dives, the conditions for your surface interval (Sunny beach or rocking liveaboard)... there really is no way of knowing "what thickness you'll need".
I dive in swim trunks, someimes a polar fleece. My wife always uses a full 3/5, sometiies a 5/7.
Take what you own, if you are a common size, rent what you might need. Until you gain logged dives comparing temperature, thermal protection and comfort....until then, no one can tell you what you'll need.