Constructive advice Asim.....
Don't dwell on lost opportunities you can do nothing about....If you want to get to know this girl then go and talk to her, because your mum wouldn't allow you to be friends is not a barrier to rekindling a friendship now.
Most people do not remain friends with their kindergarden playmates for that long anyway and so even if you had known the girl throughout school it is unlikely you would have remained that close or even in contact...so this cpuld be a blessing in disguise as friendships that you cultivate as an adult are generally stronger and longer lasting than the ones you forge in childhood.
Go and talk to her, you have the advantage that you have primary school in common and that is a basis for striking up a conversation.
Forgive me for my harshness earlier, just a disagreement on persepective due to what I was doing today.
Anyway, go talk to her and good luck.
Ps...leave the Mac10 at home....girls generally don't like guns....not that kind anyway