Aikido will be perfect for you.

I used to train with a lady of 76 and although she was no Bruce Lee she definately had the ki that Aikido will give you.

It is also intelligent, you will experience things and do things you didn't know was possible.

If you want to learn self defence then I reccomend you suplement it with something more direct and simple.

I will be bringing my Gi with me so I might see you there.

It dun't really matter.