It depends how much you weigh and how much he weighs
No, I'm 5'5 riding a 14.2 pony
I ride a 14.1 pony and im about the same height. My legs are long (for me). As long your horse isnt stuggling and you can ride without a problem you should be fine
Depending on how long your legs are ;)
It sounds like you're getting on the tall side, but it really depends on the build of you and your horse. If they have a dainty, slim build, then you may be too big, but if they are stalkier then I don't see why it could be an issue. At the end of the day, it doesn't matter how tall either of you are, just how you look as a pair. Id recommend showing people pictures of you riding your horse and ask their opinion. As long as you don't weigh more than 15% of their body weight, it would only really matter in diciplines like hunters, where you could be docked points for not appearing to be a good fit for your horse.