If your girlfriend has super regular cycles, such that her period always comes on day 25 without fail month after month, you and she could assume she ovulates around day 10 or 11 of her cycle. But if her cycles vary, and sometimes her menstrual months are 25 days and sometimes 28 days and sometimes 32 days, it is not a good idea to assume that she ovulates on a given day of the menstrual month, because she might not. It is smart of you to be concerned about the sexual activity you had, since you would have had sperm in your urethra no matter whether you washed off the outside of your penis or not, and when you got another erection and inserted the penis, pre-ejaculatory fluid could bring that sperm out into her body. Sperm flowing into her reproductive tract (whether it is on pre-ejaculatory fluid or not) is about all it takes to expose her to the risk of pregnancy. If this all happened around the time she was ovulating (which again, you can't be sure unless you know her cycles are like clockwork) then there is about a 15-20% chance of pregnancy. All she can do, as has been mentioned, is take a home pregnancy test in about two weeks.
While it is unlikely, if you put your penis in her vagina, then that is a risk. But again, very unlikely. She could take a pregnancy test if she misses her period or when it is 2.5 weeks past the date this happened. Expect it to be negative and yes, she needs to either be on birth control or you need to invest in some condoms. ppowb has given you excellent advice and guidance!!
Sex on cycle day 7 is unlikely to result in pregnancy. Ovulation is about cycle day 14 of 28, and sperm survive inside for only 5 days. These experiments go a little further each time. Have her download a period tracking app so she can get a better idea of her fertile window and correlate that with physical signs of ovulation ( fertile mucus etc.). It's time for you to have some new condoms on hand so that you are properly equipped when you decide to go all the way. Even better, she should tell her mom she is close to becoming sexually active and needs to get on hormone birth control.
No, this in no way would lead to pregnancy. Your penis needs to enter her vagina for pregnancy so no worries.