Need some advice on getting my first bike

Hi everyone. I recently took a bike on rent for 1 month ( pulsar ns 150 ), just to learn how to ride it. I believe im pretty comfortable now riding a 150-200 cc bike. Maybe I can rent it for another month for some more practise.

I wanted to know what kind of bike should I buy now ? I was interested in triumph speed and scrambler 400, duke 390 and maybe some models from yamaha. But I'm not sure wether i should go for 400cc bikes right now since I only have 1 month experience. Also getting a second hand vehicle is also a hassle since ill have to sell it later as well which is another headache.

Please give me some advice, what should I do ???