My gf and i have been friends for long time, and recently we engage in sexual activities. we both are still virgins. can we get stds or stis?

Probably not...: If all stated are true, of course, I believed it, your likelihood to get STD-/STI-related infection is slim to zero. Remember: Some men and women are still harbored with STD-related virus such as HPV as carriers. In real life, just move on, be responsible, and practice safe sex monogamously if possible. For more question, ask Doc timely.