Justin Bieber is a baby no loner. Bieber’s mom, Pattie Mallette, has taken to Twitter to share her disbelief about her famous son’s birthday. Saturday, Bieber turned 20-years-old leaving behind a year of arrests, incidents involving eggs, numerous headlines, and his infamous headshot.

With Bieber leaving behind his teen years, Mallette is having a hard time believing her son is all grown up.

Mallette tweeted , “20!? I haven’t accepted it yet. Still in denial. I can’t believe it. Not a teenager anymore.. Unbelievable. #DoesThatMeanImOldNow?

Earlier Saturday morning, the 37-year-old mother wrote, Happy Birthday YOU KNOW WHO! I love you. Xoxo.

Most recently Mallette has been in the news about her concerns about her son’s recent troubles. As previously reported Mallette only wishes the best for her son and for others to know that Bieber will make it through this difficult time.

In 2012, Mallette wrote an autobiography, called Nowhere But Up about raising her son as a young mother. The book made it on the New York Times Best Seller List according to Entertainment Wise.

Photo courtesy of Wikimedia Commons