Here are some suggestions:
Respected teacher(s) and all my class-mates present here, a very good morning to all of you.
Today, I am going to introduce myself to you. (Formal. Informal: Today I will tell you something about myself.)
As you may already know, my name is Alice. I was born in Mumbai, but I’ve been (here) in Delhi since I was less than a year old. I am 18 years old.
I have studied and prepared for my career as a (secretary). So far, I’ve completed my 10+2 from the CBSE board. I did that in 2011 and presently I am doing a secretarial course from the Institute of Company Secretaries of India (ICSI) which is in (name of the place).
I come from a large (small, average-sized) family. I have two sisters, one older and one younger than me, and a brother.
I always try to find a better and easy way to do things. When there’s a function or ceremony at my home and I have to organize (make preparations for) it, I always try to .....This tells me that I am innovative or creative.
I value honesty. I try to be as honest as I can be with my work and with the people I am associated with.
I am optimistic and industrious. The best example of this is that I don’t do things halfway. I don’t put off till tomorrow what I can do today. For example, when I am facing difficulties with something, I don’t leave that particular thing as it is, but I keep trying to find a solution until I reach a solution. (I always ask more experience people for help if I get stuck.)
t’s not that I work hard only when I’m in class or at work (if I am working somewhere). I work hard when I’m home as well, for example, I help my mother by cooking dinner for the family, by washing clothes, by doing the dishes etc.
The rest is good.