Re: it and that.... is me
Please remember that captial letters are important when writing English correctly.
It's me. (There are people who say you must say "It's I." Ignore those people.)
Caller: May I speak to Barb pelase?
Barb: This is Barb. This is she. (Many people will tell you this is very formal. They are right.) Barb speaking. Speaking.
Husband, answering phone: Hello?
Barb: Hi honey. It's me. (He will recognize my voice.)
A: Who is this a picture of?
B: That's me!
A: You were a cute baby.
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.