Question

Both of the girls insisted that they try to reach the end of the trail by themselves.

I know they and themselves are pronouns. I know both can be used as a pronoun, but I am thinking no here. Am I right?

Answer 1

Both are pronouns, yes ... and are used as pronouns in this sentence.

Answer 2

? So Both at the beginning of sentence is also a pronoun

Both of the girls

Answer 3

http://grammar.ccc.commnet.edu/grammar/pronouns1.htm

Yes, "Both" is an indefinite pronoun.
And "they" is a personal pronoun.
And "themselves" is a reflexive pronoun.

Be sure to read through the different types of pronouns on this webpage.