Company Secretary

Before enrolling for both the course together, you must know and understand the structure of both the professional courses.
Firstly, I would like to tell you about the Company Secretary course
The course comprises of three programs
Foundation program
Executive Program
Professional Program
After qualifying all the three programs, the candidates has undergo a practical training for a period of 15 months, in a company or CS firm.
After the 15 month training, the candidate has to go through another practical training for a period of 15 days in registrar of company, Stock exchange, SEBI, Company Law Board etc.
As far as course in LLB is concerned, after +2, the duration of the course is 5 years. After completion of the course, the candidate will have to appear for an exam conducted by All India Bar Council and has to complete 1 year internship, to be eligible to practice in court.
Now, according to me, your daughter should enroll for Company Secretary after +2 and law after graduation. This will enable your daughter to complete all the three programs of CS I.e Foundation, Executive and Professional program, along with graduation. After this, she can enroll for the LLb and could pursue while going through the practical training of Company Secretary course. In this way, she could manage to pursue both the courses without much difficulties, but if she decides to pursue both CS and LLb after +2, its not advisable for better results.
Like CA, CS is also a professional course which is carried out in correspondence mode. Whereas Law will be of 5 years long regular course.
She can do like this- Taken admission in CS foundation and simultaneously get into LLB, with specialization in Corporate Law it will be much better for a CS candidate if she is opting for law with corporate law as specialisation.
But things will get tougher for her to manage, as she have to manage both CS and Law simultaneously. Clash of examination dates may also create a head ache. Besides these managing both courses will take great effort and hard work to score better. Besides this she would surely have to opt for good coaching for CS and Law if required.
So, confirm with her if she is capable to manage CS studies + coaching + Law studies simultaneously.
If not better first complete her CS, then opt for LLB (Corporate Law), it will take additional 3 years to complete LLB. If she is going just after +2 will take 5 years for completion.

A company secretary is a senior position in a private sector company or public sector organization, normally in the form of a managerial position or above.
Company secretary is a professional course administered by The Institute of Company Secretaries of India (ICSI) under the Company Secretaries Act, 1980 to develop and regulate the profession of company secretaries in India. According to the companies act, companies with a paid up capital of Rs. 50 lakh are required to appoint a company secretary. Company secretary course gives you knowledge and understanding of the modern practice in corporate financial and legal affair. To become a company secretary, the candidate need to pass the foundation programme, executive programme, and professional programme that were earlier respectively known as foundation examination, intermediate examination and final examination conducted by the institute and further, they need to undergo practical training to become eligible for the membership as a company secretary.
Candidates who have passed senior secondary (10+2) can apply for the foundation programme. Graduates, post-graduates (excluding fine arts) and those who have passed final exam of ICWAI or ICAI or of any other accountancy Institution in India or abroad recognized by the Council of the Institute can directly enroll to the executive programme without doing the foundation course. Candidates who have passed the executive programme can apply for the final course. Registration for each examination should be done at least nine months before the month in which the examination is held. The examinations are usually held in June and December every year.
A candidate who wants to pursue the company secretaryship course under the new scheme of examination has to complete the following three stages:
*Foundation programme
* Executive programme
* Professional programme
Kindly, refer the links given below for more information:
https://www.shiksha.com/career-as-company-secretary-cc-30
https://banking.shiksha.com/cs-company-secretary-courses-in-india-categorypage-4-82-1-0-0-1-1-2-0-none-1-0
http://www.icsi.edu/student/careerascompanysecretary.aspx