We can go to the future with time travel but to go to the past would only be days to the past. Every atom has a quantum signature. Going to the past the atoms from then and yours want to quantum entangle and merge as one.
If you travel to before you are born you would be ultimatly oblitirated by quantum entanglement. You are 40 go back to a child. 99.9% of you gone leaving nothing traceable.
I see the max may be a few days. Go back more than a few days you could lose skin and more to quantum entanglement.
To the future you bring all atoms to where they are not but back you bring them back to where they are.