Hamsters running away from her sister

[Mikschu]

So I have two female winter white hamsters, ones name is Nashiro and the other is Kurona (Tokyo Ghoul name hehe) and this is actually my first time having two hamsters instead of one. Just a few hours ago I think the two got into a fight and Nashiro ran to her corner and luckily Kurona did not chase her. A few hours later Nashiro woke up and was eating on her food bowl. Kurona woke up a little later and when Kurona approached the food bowl, Nashiro just ran off and hid in her corner again like she was scared of Kurona and again, Kurona did not chase her or anything. Is this normal behaviour? When do I seperate them? I only got them 2 weeks and the pet shop doesn't know how old they are, they just told me they're a few months old.