Onyemachukwu - if you are seeing your dr. for regular visits during your babies first year and he is telling you not to worry - I wouldn't. My boys were twins and a bit premature. They did not sit well until they were 9 months...did not crawl until they were almost a year and didn't walk until they were 18 mos. old. - well behind most of the children their age. They are now 9 years old and they are fine. Brilliant even - if I do say so myself.
One of mine would not reach for anything either. We would place it just out of his reach and he would look at it - consider it...and then proceed just to sit and watch everything - rather than move. It's his personality. When he was ready and the object out of his reach was interesting enough...he moved. He is a great little baseball player now and the fastest runner on his team.
You cannot measure your childs motor skills or verbal skills by other children. As long as your Doctor says not to worry - I would not. You cannot take the child to the Dr. every time you have a question about a growth issue. You can call the nurse and she will field the question for your Dr...asking him if she thinks there is a problem and suggesting you come in, if there is a possibility. At least that is the way mine works.
There are many children that do not crawl very much and will take up walking before they have crawled long. So the fact that yours is standing and up on her toes is not concerning to me.
Raising babies - especially your first does come with a lot of worry. It is nice to get reassurance from others...and of course it's okay to ask questions here. Most people here are just very thorough before they give uneducated advice. Which is very wise.