Why are they not autonomous persons
Because the unborn are dependent on the beating heart of the body in which they reside. If there is an unborn 'will', it is subject to the autonomy of the body they need for their existence. If I rely on your organs for my survival, I exist solely by your willingness to allow me to use them. I have no claim to your body, while you do have claim to your own organs regardless of my needs or wants.
Personhood is a legal status which is typically granted at birth or in rare cases involving malicious harm of the person they rely on for life.
Also, did you know that abortion changes a woman's body and life as well?
Pregnancy is the cause of change in a woman's body, not abortion. Abortion stops the pregnancy, but it may not stop processes already begun.
you are talking about sticking instruments in a woman who is already pregnant and killing her unborn child.
Most abortions occur early in a pregnancy and medication is all that is required. Abortions which occur later in the pregnancy (and might use instruments) are typically done out of necessity, such as to save the life of a woman who most likely wanted a child.
There's Hormonal changes, breast tissue, lactation and even changes at the cellular level because of abortion.
Without abortion, these changes will occur demonstrating these changes are due to pregnancy and not abortion.
Also, comandeering a body isn't the same during rape and you know it. With rape it is done with intent to harm,
Rape occurs any time there is non-consensual sex. Intent to harm isn't necessary. Comandeering someone else's body for personal gratification or benefit is, in itself, harmful to the victim.
Are you for the death penalty?
Abortion is about disallowing occupancy (not an execution). I am a strong proponent of eviction. If I, as a property manager, evict someone from my property, I haven't executed them. I have removed them from my property and they, being fully autonomous persons, are responsible for their own life regardless of where they live.