Definitely agree with Joseph41, in that Eng Lang may not necessarily be tailored for you if you're a Maths/ sciency person.
Personally, I love English, so I'm doing both this year! English and Eng Lang.
And in Year 11 I found out that both of them helped each in some way or other! For example, English helps me understand the nuances of words in Eng Lang or even some social purposes.
And then Eng Lang helped me with Argument Analysis for English because I could go into the nitty gritties of grammar and understand connotations of words!
I feel like Eng Lang is so much skills based, that's what I like about it! Once your concepts are crystal clear, it's all about application and sticking to that formulaic AC or SA format.
And then you've got texts, poems, etc to study for English - the comparative's the new one, which to me is really exciting!!
But definitely like lovelyperson said, you might not be familiar with metalanguage in Eng Lang, whereas you'll have some knowledge from Year 10 English. But having said that, the metalanguage shouldn't be too hard to learn if you practice a lot and you notice things in daily life in conversations!
So mainstream English'll be your best bet!
(Sorry if I was all over the place! Just wanted to share my opinions about both Eng Lang and English)