Good job on the normal english, people will be alot more willing to help you if you talk normal like that..Makes ya seem alot more mature ;)
as for telling you mom...That could be hard..Maybe you'd be more comfortable someone was with you..An aunt, a girlfriend, neighbour..Someone you trust and can tell frist. If they're there maybe she won't over-react. And they can be a sort of unbaised barrier between you two. Thats what i'd do in your shoes atleast.
Have you told ur bf yet? And his parents? If they're more supportive maybe you could stay there while your mom has time to cool off and process everything...
Good luck