MacBook Air shuts down w/out warning - battery % incorrect

Hi - recently my MBA has started shutting down at random times while not plugged in. Sometimes right upon signing in. All the times this has happened, the battery charge has been fine and well above 50%. However when I push the power button to turn it on after it shuts down, it gives me the black "No Charge" screen as if the batter is completely dead. I plug it in and it turns on fine with the correct battery charge shown as before shut down. I initially thought this was a memory issue while using Photoshop, but I think it's a battery issue now. SO - am I able to change my own battery in my early 2015 MBA not being a techie? Do you think that's what's going on? (I'm asking because it's hard to get an appt at Genius Bar right now and MicroCenter was ZERO help when I made an appt with them.) THANKS!