Newbie IPO investor here, please advice

So, I have some money to invest in IPO, I have made losses in FnO and gave it up few months ago. Due to those losses I have lost confidence and hence stopped trading. I applied and later cancelled my application for Mobikwik IPO only to see it getting listed at more than 50% gains. I wanted to ask fellow experienced IPO investors, is GMP credible if one wishes to obtain listing gains. Also, is there a delay in listing and share allotment, I saw some reviews stating it takes 24-48 hours to confirm allotment after listing. If that's the case then will I not be able to make listing gains.