Can't sign in into my Minecraft account (android)

Hi, so recently when I booted up Minecraft I saw that my ign was Steve and I wasn't signed in. So I clicked the sign in button and entered the account details and clicked continue. My Minecraft started booting up again and when it did my ign was still Steve and I wasn't signed in. I already tried reinstalling Minecraft, but it didn't work. If I made a grammar mistake English is my 2nd language.