I ejaculated in my pants and we tried having sex but weren't successful

It would depend when her last period was, how long her cycle was, if she is regular and was her vagina wet to whether she could get pregnant from it but your right to be concerned because even though you ejaculated there would of been sperm left in your urethra, it might be a wise idea to use emergency contraception just to be sure.

Hi, thanks for your reply. As far as I know
She has regular cycle of 28 days. Last time she has period on 7th Feb 2018 & we had it on 25th Feb 2018... ttechnically I have not ejaculated inside her and my penis was wandering her outside vagina that's all... Will it harm her body and can she take emergency pill now?? What would be your suggestion.

If the date is correct for the start date of her period then by the 25th she should of been past her fertile point, there is a chance that sperm can swim into the vagina from around the entrance if she was wet enough at the time too. Using emergency contraception as a one off won't do any harm it may just throw her cycle out of ballance for a few months that's all, most emergency contraception can be taken up to 72 hours after the event happened but it's always best to take as soon as possible as the odds of it being successful lower with time.
As I said it may be a wise idea to use it but the decision is yours.

Thanks for your reply. Itseems My girlfriend disagrees. She says she will drink Papaya juice and it will balance it out. I just know that what are % chances of not getting pregnant. She says she will wait till 15th of March. What should I do? Even she is panicking a lot due to this. Also there is strong fact that I did not inserted my penis inside her actually. I guess I had I started wandering her vagina after 10-15 mins of ejaculation. Please help.

If the emergency contraception was shown to do any sort of harm to the body it wouldn't of been granted a medical licence to be sold in so many different countries as it has.
The chances of pregnancy would be very low but there is always they 1% chance, even though you say it happened 10 to 15 minutes after you ejaculated there would of still been live sperm in the urethra that could of gotten squeezed out unless you had predicted between ejaculation and contact being made.
I can't tell you no more than I already have and only you can make the final decision on what to do but if you go against what she says then you will be losing her respect.