I have a brother who is 17 and a sister who is 13. Do I need any type of consent from my parents? In regards to traveling to another country. Such as a letter or anything of that sort? I am currently 19 and I will be traveling with them.

Yes, you can not travel with minors internationally without notorized consent by both parents.

If a child (under the age of 18) is traveling with only one parent or with someone who is not a parent or legal guardian, U.S. Customs and Border Protection (CBP) strongly recommends that the accompanying adult have a note from the non-traveling parent (or, in the case of a child traveling with neither parent, a note signed by both parents) stating “I acknowledge that my wife/husband/etc. is traveling out of the country with my son/daughter/group. He/She/They has/have my/our permission to do so.” CBP suggests that this note be notarized.  If there is no second parent with legal custody of the child (e..g., the second parent is deceased, one parent has sole custody, etc.), relevant paperwork such as a court decision, birth certificate naming only one parent, death certificate, etc., would be useful as well.