"People shouldn't try and share their beliefs." Discuss

I have never been so thankful for the RE curriculum...

My little (probably not a Christian) sister had something like the title to this post for homework. I'm still happy that she rung me up to ask for help and I got to share more of the Gospel with her than I have for ages (and with her actually listening carefully too!).

I'm also thankful for God actually giving me the words to communicate relatively clearly for once (ala Mark 13:11). He gave me three points off the top of my head, and some good verses to back it up (she wanted sources!):

1. There is one God for everyone, because he created everyone: "is God the God of Jews only? Is he not the God of Gentiles also? Yes, of Gentiles also, since God is one" (Rom 3:29-30)
2. The Gospel is good for everyone (cure for cancer argument): "'everyone who calls on the name of the Lord will be saved.' How then will they call on him in whom they have not believed? And how are they to believe in him of whom they have never heard? And how are they to hear without someone preaching?...'How beautiful are the feet of those who preach the good news!'" (Rom 10:13-15).
3. We're commanded to tell everyone: "Go therefore and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, teaching them to observe all that I have commanded you" (Matt 28:19-20).

Anyway, that's not really a usual post. And I'm sorry for the lack of blogging recently. But opportunities with my family are rare, and I just feel compelled to share it (bit like you should burst to tell the gospel - although I too rarely do). And I suppose I'd like to ask for quick prayers for her if you get a moment. Thanks!

You can always tell me what I should have said too, because I guess I only focussed on giving an answer from a Christian point of view - but I'm not really sad about that.