A new credit account can affect your credit score in a few ways. However, it's impossible to say how much because it depends on everything else in your credit report.
First, the inquiry into your credit report will impact your score. Next, the new account will affect the average age of the accounts on your credit report. Third, I presume you are getting this loan so you can borrow, and a new account with a balance will affect your score.
If you need the loan, the terms are decent, and you can realistically pay it back in a reasonable period of time, then proceed. But if your credit is on shaky ground, and/or the loan is expensive, try to explore all your options before moving forward.
