That's not relevant - what's relevant is the length of time for which you had the mortgages.
1. Did you get your first mortgage more than seven years ago?
2. Did you get your second mortgage (that is, with your wife) more than seven years ago?
If the answer to both (1) and (2) is yes, then neither of you qualifies as an FTB and the maximum relief you can get this year is €1200.
If the answer to both (1) and (2) is no, then you may both still qualify for FTB relief and the maximum relief you can get this year is €4000.
If the answer to (1) is yes and the answer to (2) is no, then I am very nearly (but not totally) certain that you can use the remaining period of your wife's FTB status and your standard relief, making the maximum relief you can get this year €2600.
And if the answer to (1) is no, and (2) is yes, I'd like a go on your time travel machine please!
Remember that the relief allowable is 20% of the interest actually paid or the maximum amounts above (depending on your circumstances), whichever is the less.
Hope that helps.