I wish all the best to both of you. It's good you celebrated your wife's birthday with bitcoin earnings. I thought you gifted Bitcoin, but I clearly understood when I read the full post that you bought a gift with your earnings from Bitcoin. However, I feel a direct Bitcoin gift would be more memorable; I mean, gift some Bitcoin to her wallet. Since it's already past, you may plan for the next birthday. A bitcoin gift might give a good return in the near future as well, which would be special for both of you. Anyway, you did good and appreciate your wife's gift, which is BTC writing and logo.
That's also my first assumption based on the title alone. However, I agree with you that probably by next time, it will be more valuable if the real btc will be given to his wife. Not only it's a good investment, but it will also be a good retirement in the future. I believe your wife will be very happy for that knowing both of you have higher knowledge about bitcoin.
For now, plan it early so you can save btc as much as you can. But regardless if it's big or small amount, that will still be huge in the future once she decides to hold it for couple of years.