Baby staring at hands?

My baby is 3 months old and has started to look at her fists. She seem to be trying hard to put her fist into her mouth but don’t succeed yet. Is this normal for her age? Update: Baby started to suck her hands already. Babies develop at different rates and we just got to have faith and not worry too much. Unnecessary comparisons like “oh my baby can do that at xx number of months and so do other mummies” does nothing but exacerbates other mummies’ worries. Let’s all have faith and spread kindness.