Quick drain of battery in new phone huawei g play mini? Here is a screenshot of my battery drain.

Is it normal , or should I go to service center ? My previous phone had much less sloppier curve . When I bought the phone I charged it upto 100% and then started using it , though at the shop they told me to charge for 3 hours. Should I go to service center? The problem is battery(2500mA) is fixed in this device , so I can't even remove it.
By looking at your screenshot I think you should wait a few days to see if your new device settles down a bit on battery usage.

Why do I say that?

Even though your battery is draining fast when your screen is off, there are not many wakelocks. Give your phone a little bit off time to settle down ( syncing data between all accounts etc.) and it should be fine. If you're still observing heavy battery drain after 2-3 days, then you should go to the service center.