Accounts can be merged, but when it comes to the progression on those accounts, it becomes tricky.
According to this article: [EA Help] - What to do if you've accidentally made a second EA Account
So in this case data will not be moved from one account to the other, so I believe it depends on the way you merge it.
They could potentially merge the newer account into the older one, meaning you won't have the data from the new account but keep the data from the older account and vice versa.
Though since I don't know this 100% sure, I think your best bet is to contact EA in this case.
For this specifically you can use the link mentioned in the article I posted before, or you can go to it directly via this link: [EA Help] - I want to move my stuff to another account - EA Account
Hopefully that clears up the confusion, if you have any further questions, ask away!