SMS unread count app any good? Or is it malware/spyware/virus?

Google are generally pretty good at keeping malicious apps off the Play Store, so it should be safe.
If you're still unsure, you can download an antivirus and scan it.
 
I'm literally brand new to android and worried that everything is malware or a virus that I download since downloading this. It's just I've noticed that when playing PvZ2 it could be smoother and then switching out of the game it SOMETIMES stutters, it has crashed a few times (haven't tried it since update) and I thought it was supposed to be lightning fast. There seems to be a slight issue with Firefox in that it flickers when searching sometimes. I can't tell you how new I am to this seriously. I feel like a **** asking these questions.