As a Border Patrol agent for the past fourteen years, and a current national recruiter, getting in contact with a recruiter can greatly assist with guidance on this journey.
I hope you continue to look into joining the Border Patrol, it is an amazing and rewarding career.
²Entrance Exam study guide https://www.cbp.gov/document/guides/bpa-entrance-exam-preparation-guide
³Entrance Exam Pre-test https://tara.vitapowered.com/WorkflowEngine/CustomUrl/CBPEntry/CreateCandidate/BPAPractice) Since I do not know of your personal aptitudes, the info in those links will help you answer your own question.
Your next priority is fitness! Krav Maga, BJJ, wrestling, MMA, Muay Thai, boxing, HIIT training with explosive movements are all preferred skills that can save your skin should the need arise. HIIT Training & kickboxing in a weighted vest with ankle & wrist weights in will expedite the level of fitness required. Check with your doctor first. Busy day? 15-minute options are on YouTube & the FitCoach app. SOMEthing is ALWAYS better than NOthing! "If you knew you would be in the fight of your life tomorrow, would you change the way you train today?" -Bruce Lee (paraphrased)
Third is having a "working knowledge" of Spanish & English. Test your DELE B1 (intermediate) skills here: https://youtu.be/5Am-TbK59SE. Take the DELE/other certified proficiency test. Easy? Try B2, C1 or C2 to level up.
Hard? Try DELE A1 or A2. Affordable online DELE & other proficiency test-specific tutors at https://www.italki.com/en/teachers/spanish.
Lastly, you could opt to wait 1 year in favor of first applying to be a Fullbright Scholar in another (preferrably Spanish-speaking) country to beef up your resume not to mention have an amazing experience that's fully paid for AND pays you! Oct 11, 2023 I think is this year's deadline for July 2024 placement! (Fields of study for US students here: https://fulbrightscholars.org/awards/search?query=&field_award_multi_country=All&field_award_type_list%5B8323%5D=8323&field_award_degree_reqs=All&field_invitation_req=All). If not a Fulbright, there are other paid out-of-county internships & nearly free universities (international university means credits can transfer) you can attend to make your resume stand out. (Try those in the Schengen Zone in Europe https://www.schengenvisainfo.com/schengen-visa-countries-list/)
Forgive the seemingly long answer, but all those links take up space. Without them though, this answer would be incomplete. Best of luck to you! Train & study hard! Get that resume ready!