My 3months old baby cultivate d habit of sucking her thumb(finger) weneva she wakes up.i've tried gloves on it?

While it may be normal, it's not good. I sucked my thumb and it made it so I had to have braces (the roof of my mouth is shaped like my thumb) and even after braces my teeth are still crooked. Try those mitton things they have that keeps babies from scratching themselves. I know you said you tried gloves but you could try putting two pair on. If she still sucks on her hand then that's fine, just so long as she is sucking on her whole fist and not just one finger or something. By sucking the fist the baby learns about how it works and such, but sucking on the thumb just causes teeth problems. Also try pacifiers. Thats what worked for me. Lots of people say they bad (not sure why) but it's better than buying braces later.