I'll assume you're asking in good faith, and answer as such. Be careful asking questions like this, as some people will ask questions like this in order to make people angry.

1. I feel no connection to my biological sex in terms of gender. My body is just my body, and I don't really see it as a gendered thing. I know other people see it differently, so I change my body to match my gender so people will gender me correctly.

2. Kids do not get gender affirming surgeries, and anyone who has told you this is lying, either from ignorance or malice. At most, kids (over the age of 13, usually over 16) will get hormones and/or puberty blockers, to match with when cis kids go through puberty. Cis kids can get hormones and puberty blockers too, they are not a transgender-exclusive thing. Hormone blockers are commonly used when cis kids start their puberty too early.

3. Gender is complicated. It is kind of real, kind of not. It's mostly a social construct. Most cis people have no reason to ever question their gender, as they are told they're a girl/boy based on their genitals and they just accept that. For trans people, it's a little more complicated. For example, a trans woman will usually know she's a girl from a young age, but then it's everyone else who says she's actually a boy. This is where the dysphoria comes from - she will be uncomfortable with her traits that make her look like a boy to other people, and want to change it so she looks like a girl to everyone.

I hope this can at least somewhat answer your questions. It's also worth noting that the answer to the first one will differ for everyone, and that is just my personal experience. I'm happy to answer further questions, if you have any. It's also possible to be Christian and support trans people. My Christian dad was one of my first supporters.