So for you it doesn’t really apply, because women don’t have a mitzva per say to learn torah. Yet it is a very commendable thing to do.
It isn’t bitul torah if one is just reading it because if they were really trying to learn, it would be to their fullest potential and no one can criticize one who is trying their best. its between them and hashem.
Also I forgot to include that the mihalech is to be mikayem the MITZVA of learning torah, not just stam learning.