It's great to hear you are thinking to spend such an important birthday in Ireland!
Will you be arriving straight to Galway? The route you mention sounds like a great idea if you want to stay in the cities. However, I would also suggest you combine some of the ideas from our Cliffs and Coves trip
and our Southern Peninsulas trip
if you want a bit more of nature and visiting villages. The south of Ireland is extensive, so I would also suggest you stay longer in either Cork or Kerry and you don't rush your trip when you're in this part of the island. You might also really enjoy a visit to either Killarney or Dingle (or both) and exploring the Ring of Kerry and the Dingle Peninsula.
Let me know if you like these suggestions.
Have a nice day,