Good sentences, Ashley! I will just make one correction that you could choose to use...
For the first sentence, you had a good catch with "maturer," but the proper grammar is "more mature." English is so confusing like that--sometimes it's an "er" at the end of a word and sometimes it's a "more" before it. In this case, the sentence would read, "She is more mature than she looks." I also edited the end of the sentence a tiny bit. Great job though, girls!