Do you have fairly pale skin? I'm pretty pale and you can see some veins on my face too. One that especially bothers me is under my left eye - I always have to put concealer on it! :) I think that the density of your skin also changes a bit throughout life. If you are concerned or have any pain with it, I would see a doctor just in case. Otherwise, I think you are fine.
I'm pretty young and I get veins on my forehead too very easily. I don't think it has to do with getting older