i just need a little information..

Okay so me and my boyfriend had sex on the 2nd of December and I was ovulating and we didn’t use protection. He said he pulled out but he did also say that he might have came out too late. And I get my period on the 20th but i guess my question is how soon will I be able to test. Also like today at my work when I used the restroom when I wiped, a little bit of spotting appeared and I know it may be too soon but I don’t know. Can anyone like help me out please I’m open to anything really. Thank you.