Help plz i dont want my hair turn green!!?

Ok so last year as my 14th birthday gift i got my hair bleached (bad choice) i got a full foil so it wasn'ttcompletelyy blonde. She did a good job on the top my hair but she fried the bottom. Sheover bleachedd and it was practically gray! so that was done last year in october and im tired of it so i want to die it back to my natural color which is dark auburn brown ...is that safe? since summer is coming up ididn'tt know if it would change color because of the chlorine in the pool? plz tell me ur experience and if this is a good idea thnx sooo much=)