I heard that they usually go up 3 to 6 months of age. You can trim the ears and then tape them up if you want. Someone might come along and explain how you would go about doing that, or you could try google. I forget the site I used.
My Koda's ears haven't gone up yet, but he's just 12 weeks. I just trimmed them not to long ago, and the seems to be helping. If I need too I will tape them. Hope I helped, GL!