If you had no income in your first state of residence, then you can file a part year resident return for your second state of residence, reporting that you lived there beginning in July. However, you may want to file a zero due income tax return and and indicate that your residency ended, so the state updates their records if you have ever filed an income tax return in the original state in the past. You can file a paper return to do this.
Here is some information you may fund helpful: Tax Tips for New College Graduates
