I have a m&p 9.. it was my first handgun. I really like, at beginning I didnt know which to choose. then I bought a glock 19 and the m&p shield(still keep and love my m&p FS)
The CZ should be a good option as well, I havent shoot one yet. But they are quality guns.
The problem with those guns is the aftermarket parts if you later decide to upgrades some parts.
My advice will be start with a 9mm. As a new shooter probably you will want to shoot a lot and need practice. the 9 will be cheaper. of course, if money is not a factor then forget my advice.
Try to rent both, and then decide which one do you like better and "feel" better. the problem with this is when one is a new shooter one doesnt know how to shoot properly.
PS: dont worry, whatever gun you pick, it will no be the first, you will get both in any other hhahhaahaha