They will if it's clear from your resume that you took 6+ years to graduate. It's a reasonable concern for an employer, since the cause is often different from yours (namely, lack of effort).

So, as other have suggested, don't make it obvious. It's ridiculous to see the year of high school graduation on a resume anyway. Also, you don't have to list internships from your first two years.

If it does come up, or if they ask about it, do not lie. The appearance of hiding anything is a red flag. Just tell them that you were dealing with personal issues, and that they are resolved now. So, it won't affect your ability to perform the job.