What am I parenting?

So if you have read through any of my posts I am sure you have figured out I have two children... Unfortunately I was raised in a very strict home so I have so many questions on how to raise my children that were never answered or even discussed with me growing up.  My 12 yr old son is full blown teen. (oh my word). Then I just took my 9 yr old daughter to the dr this past week to have him inform me that SHE is going through puberty as well... Oh Heavens What do I do? 
I guess I am what was referred to as a late bloomer I am still waiting on my "buds" to come in... lol Now this whole new part of parenting scares the ever living crud out of me. I could have sworn the "teen" years didn't officially start for me till I was closer to 16. What or how do I talk to my kids now without seeming scared (as we know they can always sense the fear).  I love my children more than life itself and I do my best to raise them with christian beliefs and morals but I can't seem to find the chapter in the Bible about puberty. 
Are my kids growing at a normal rate? When do I discuss the birds and the bees? Do I put the fear of STD's in them so they are too scared to think about sex right now. lol I was raised with don't have sex period the end kind of mantra. I am at the point I am just telling my kids to please wait till they are out of school. That school is the most important and they will have plenty of time to date and do THAT sort of thing after they are established in their careers. It has helped me in being a single parent to be honest with the struggles.  
Both of my children seem to understand this concept this far. My son talks about a girl at school he likes but won't tell her because he's only in 6th grade and he has at least 6 more years of school to go.. I think in my head ADDA Boy but am I holding him back from another social interaction he needs? Am I being too strict? I want my kids to grow up and know right from wrong but I don't want to give them too much leniency to where it comes and bites me in the toosh.
I am still learning the consistency thing which does prove to be a little more difficult then I would prefer. I know my kids are going to grow up and be alright just wish I knew of better ways to handle certain situations that arise out of the blue like this one. I am not ready for my kids to be teens or in puberty. I am not ready to have the constant battles I see my friends having with their kids. My kids thankfully still like to cuddle and be loved on. I cherish each of these moments as I know one day they won't be there anymore. Sorry for my rambling today just kidna hit me like a rock.