I don't think you will get a senior discount if you're not from an EU country. I'd like to congratulate you, however, on going to the Alhambra. I cannot believe anyone would go to Spain and miss it. DO book ahead, as it's very busy and if you wait till the last minute you'll be forced into an expensive tour and have to go through it too quickly. I think the idea of entering at 2pm is fantastic if you get to stay till 8pm. It's absolutely magnificent lit. I will say that out of all the sites I've seen in Europe, this one, to me, was the most spectacular. Get the RS podcast or whatever, and really learn about it. I hope you're going when the gardens are in bloom. Make sure you're ON TIME for your entry, as they will turn you away if you're not! If the ticket says 2pm, you'd better be there, They give a little grace time but not much, and it can be tricky if you're driving there.