Should I wake my baby up to feed?

No. Infants have variable feeding patterns/timing and if they are gaining weight appropriately they can be allowed to feed on their pattern, unless it is too frequent. In general an average of every 3-4 hours is typical. In addition waking a baby to eat is easy but keeping them awake when they want to sleep is more difficult.
No. Your baby will wake up when her body tells her she needs to eat. Unless your pediatrician is concerned with your baby's growth, or she has a rare medical condition that requires frequent feedings, take any sleep you can get.
Yes. Well, i answered a very similar question recently... For the first two weeks or so, yes, at least until the baby proves to me that he/she is going to eat enough to gain weight well. Most babies, after that stage, will having their feeding schedules down well enough to not have to be awakened for feeds anymore. Remember, that sleeping a lot early on may be a bad sign of serious problems.
Yes. In general no, but that is only after the initial newborn period and once the baby has demonstrated good weight gain with your feeding schedule. Until that happens (usually 2 weeks or so) babies should be fed nor later than every 3-4 hours. After good weight gain (and no other issues like jaundice) then no reason to wake a sleeping baby if otherwise healthy.