YES. It is normal, but it will continue until:
a) Baby is all grown up. (Not likely)
b) Baby is dead (sad, but true.)
The only thing to do is separate them.
when it is the pet of the month
yes, you should bathe your guinea pig once a month.
Once A Month Is Normal ...
You should cut your guinea pigs nails once every month.
i recomend that you don't
yes
Once A Month...
yes. I had a 2 year old guinea pig and a 6 month old and the were great together.
get a trainer or everytime it bites tell it off
Well actually yes, they might fight. Males guinea pig's in general tend to fight with another therefor, it is a better idea to have two females or a male and a female together. But some males can get along, but usually males tend to fight.
not often... only like one time every month because its expensive and i don't recommend you buying one from Petco i once bought a guinea pig from their and he died a week later and then i bought a hamster and he died within two months i do then again recommend you talking to a breeding and getting one through them or adopting one from a small pet animal shelter.
most guinea pigs are longer than this. My baby guinea pigs get this big when they are only a month or two old