Ay, understandable ang worry mo, mama! Seven months is still within the range where babies develop differently, some of my mum friends' babies were quiet too at that age pero by 8-9 months na may sounds na, kaya hindi pa rin sya red flag. That said, it's best to bring it up sa pedia mo next visit para ma-check kung lahat naman ng development markers niya (like grasping, sitting, responding to sounds) ay okay, baka lang talaga sya quiet baby, o may something na kailangan i-address early.