Hello Balaji,
If your ultimate goal is engineering then you can go for Diploma then Lateral Engineering. It will be more beneficial because you will be eligible for Junior Engineer post as well as above post.Some engineering department don't allow B.Tech holder for JE Post. they only hire diploma holders.
But in any case, where intermediate certificate is required, You will be not eligible for that post.
If you do 10+2, then you have chances for government engineering college if you study well in 10+2.
Otherwise both are almost same.
Good Luck.