Aqeeqah is sunnah on the seventh day of birth. If it is not performed on seventh day it will cease to be mustahab. If aqeeqah is performed after seventh day then it will turn nafl i.e. this will also deserve reward but now as much as mustahab. Therefore, one can perform aqeeqah after a year also, but it is better to take consideration of seventh day e.g. the child was born on Friday then the aqeeqah should be performed on Thursday.
Allah (Subhana Wa Ta’ala) knows Best
Darul Uloom Deoband