We recommend requesting feedback from as many peers as possible. This includes asking your current peers in addition to people that you worked with in the past.
These are the people that you are working with on a weekly basis. You'll want to ask them for feedback and ideally receive feedback from them once a month. Monthly feedback has been shown to lead to increased work performance.
Asking former peers for feedback is highly encouraged and a great way for you to quickly learn how your skills have progressed over time. If it's been less than two years since you worked with someone, don't hesitate to ask. Better late than never!