You are never prohibited from Special Summoning unless not an effect specifically states so (Archlord Kristya, Pot of Duality, etc.) and if you don't meet the summoning conditions (as in, trying to Special Summon Dark Armed Dragon while you have less/more than 3 DARKs in your graveyard, trying to summon High Priestess of Prophecy with own effect when only having 2 "Spellbook" cards in your hand, etc.) - if none of the above applies, you can Special Summon during your first turn.