While it is canonically legal to celebrate Sunday Mass on Saturday evening (or Sunday evening), I find it a much richer experience to attend Mass on Sunday morning, as the Mass was meant to be linked to sunrise and the coming of Christ (which is also why our churches are meant to be oriented to the East).
Simply put, if you have been attending Sunday morning Mass all your life, I believe you should try to continue doing so, unless there is some new reason that makes it less convenient for you. If you have been attending Saturday evening Mass all your life, however, do give Sunday morning a try. You’ll find that the morning sun (especially if your church has glass windows behind the altar) can make it feel a bit more special.