hi
when you say "this bag is too heavy" it means that it is too heavy to be carried.
but when you say "the bag is very heavy" it means that it is heavy but still you can carry it
as for the sentence "she is too beautiful" I don �t think we can use it like this
It is better to say "she is very beautiful"
Maybe you can she is too beautiful to be the 2nd runner in the beauty contest.
what I mean to say is that when we use too + adjective there should be a completion to the sentence and you should not stop at this only "she is too beautiful".
I hope that I helped.