Well of course, the 12-week limit is pure horseshit. Literally nobody in ethics makes this argument it’s merely invented by supremely ignorant lay persons to pander to both sides.
You only feel that it is an argument for later abortion, because you are affirming the consequent (a laughably stupid logic error to make) by assuming that abortion is already permissible.
Either killing humans is permissible period or it’s not. Dependency and development arguments fail to provide exceptions that don’t also apply to adults.