Pledge loan: 36 months, or longer?

I'm a NFCU member rebuilding my credit. I also want to strengthen my NFCU relationship. Currently I don't have installment loan payment history on my credit report (I do have federal student loans but they have been deferred and no payments have been made). I don't have a mortgage or an auto loan. I recently learned about pledge loans (that automatic comment in this sub is good info). I think it's worth it to open an installment account and make regular monthly payments, based on my research and my understanding of my credit reports.

I am using $12,000 for a pledge loan. Immediately paying off $11,700 and setting payments on autopay each month.

I'm planning to go with 36 months. It's longer term, and it's a decently large loan. I plan to apply for auto financing with NFCU in two years, it would be nice to go into that with two years of on time payments and a low balance on the pledge loan. But - I know I can go up to 60 months. Is there any reason I should consider more than 36 months?