It won't make much difference. The difference will be significant if you apply more than 5 years after graduation.
2) If I go for my electives and do my CS at the same time, would it affect my visa application?
No. Just be clear and honest about the reason you are heading to the U.S. during your visa interview.
3) How long before my electives do I need to apply for my visa? Do I really need to wait for the elective approval letters before applying for the Visa?
Generally, you should apply for a U.S. electives at least 6-8 months before your elective period. Complete the application as soon as you can. Visa application and processing may take from one week to one month.
4) What kind of questions do they ask you during the Visa interview? Are Malaysians generally approved for Visas without much difficulties?
It's easy to get a visa as long as you are honest. Just clearly state the reason you are heading to the U.S.
