You provide very little information other than to say you were arrested while protesting. That said, I bet a lot of people in social work have been arrested while protesting. So you'll be in good company.
Also, this happened to you at a young age.
If you're really worried, speak with an attorney. Find out how long a charge like this stays on your record and whether there's any process available for you to have it expunged.
And is what you did actually considered "criminal"? If so, that's ridiculous but besides the point.
Basically, don't worry about it, you'll be fine, and there are plenty of people who have come before you with more serious charges on their record, and they were still able to successfully obtain licensure in similar fields.
If you absolutely must disclose it on an application, be sure to explain it. Don't assume the reader will understand these kinds of things are part and parcel of the current police state we now live in. And depending on how you want to spin it, you can always pass it off as a youthful mistake from which you learned X, Y, and Z.
Good luck to you.