Is getting a girls number without her giving it to you a foul move in a new relationship?

Anonymous
Ok I couldn't exactly get the wordings to be short and what I meant at the same time for the question title so bear with me a little longer and read my description.
I started dating this girl last week, and she gave me one of her phone numbers, the one connected to her work account on telegram, now I do have her main personal account on telegram, but not her main personal phone number. She mentioned she likes the guy she is dating to be smart. And I mentioned to her I am not very smart, but I have a pretty decent perception and analysis.
She has studied software engineering like me, so she understands programming.
Here goes the real question, taking into account all above, how would it look if I could get her main personal phone number by a programming trick I know (not by hacking or violating security or privacy matters) and then asking her if she thinks I can do that, tell her I did it and at last explain How I did it afterwards. Would this be a turn on or a turn off? (Please Take into matter every aspect of what I explained first before answering.
And be neutral towards me and my intentions, I just want to really impress her.)
Is getting a girls number without her giving it to you a foul move in a new relationship?
2 Opinion