Met this guy

So I met this guy at a birthday party with his sister! He sat next to me and we talked. I thought he had amazing energy and I believe he felt the same way the way! I went to take photos and I saw him smile and stare at me and I stared back when I looked back he was gone.

His sister in up following me on social media and he does not have social media. I didn’t want my friends to know my business and I was afraid but I dm his sister and asked I could contact him because I was interested in getting know him.

She told me she asked him and he said yes and she sent me his number.

I texted him with my name and letting him know I met him at the party. He has not texted back. What should I do? Should I be worried?