A bit more about my lifestyle:
I go out at about 8am for school and I get back about 3:30pm. This is an hour and a half before my mum so therefore it will be ME taking it for a walk. My mum works 2-3 days a week so the rest of the week she will be able to let it out into the garden during the day. Sometimes it may even be one time a week for 8 hours as on Tuesdays I get home at 2pm. I do have a back garden which is quite large. My mum has not said yes or no yet so I am not being a whiny brat, she just wants a few things cleared up before she thinks of getting one. It will get walked in the morning for half an hour no matter what the weather and I have pretty much all night for an afternoon walk.
I'm wanting to get a rescue dog from our local shelter so I'm aware that it will most likely be a mongrel but it will probably have the characteristics of the parent breeds.
If there is a big dog breed that you can think of that is generally well-tempered and non-destructive then please could you post that too :3