Looking for some advice.

Miriam
Hi so am 18 years old and have been thinking of getting birth control for  2 main reason. The first is that I am sexually active and feel like a second pregnancy prevention method wouldn't hurt. The second reason is I am HIGHLY unregistered!!  I am so irregular that I can go up to 5-6 months without my period. 
I would like to hear your experience with birth control and which methods better and also if anyone has the same problem as me with the irregular period and any thoughts of what it could  be and what could help. Please and thank you💋💕