52 is standard for any account; also Dragonborn does add another slot - if you get one from first time buyer's pack as well (don't know about that) that would be 59 possible slots atm.
Seriously following the previous time schedule this one would've been on the late end already but another 3 weeks? We want new mods every 3 to 3 1/2 months! Another 3 weeks of nothing to do ingame.... Bad decision imho, of course there'll be bugs upon release but it's never going to be perfect.