You can try the needle wise tell I did it tonight and it said boy for me. My niece did it early in her pregnancy and it said girl. She's 6 months now and it was right for her. Its fun.
It's recommended that you are after 16 weeks anything earlier may be wrong. During your anatomy scan they can go ahead and let you know.
18-20 weeks is when they usually do us to see if there not hiding that is :)