4 month checkup

Just wanted to give you Luli's measurements. She had her 4 month checkup yesterday and was such a brave girl with her vaccines! She now is 24 inches (25-50 percentile), 12.3 lbs (10-25 percentile), and her head is 15.3 inches (below 5th percentile). Ok, she has a little head:) She didn't gain so much weight from last time but the doctor isn't concerned yet. She wants to see how she gains next month. Hopefully she'll put on enough weight.
also, a question for you moms, have you vaccinated your babies with the pneumonia/meningitis vaccine? The doctor told us we should do this in March, but I think its optional. I'm just not so sure about all these vaccines. How are we suppose to know which are necessary and which aren't?
on a side note, Luli is rolling over so good now from back to tummy! and once she's on her tummy she gets her bum way up in the air and pushes forward like a little inch worm. Its so cute to watch but I'm a little nervous about her being mobile. I guess I'll be keeping a very close eye on this little bug!