I would wait till I got responses from all my beta readers. They were nice enough to agree to read it, you should wait for their opinions.
HOWEVER, WITH THAT BEING SAID, if it’s been a while nudge them, offer to let them off the hook - something.
I had a beta reader - who offered, I didn’t ask. It was over 4 months. I had received all my other critiques. Had made changes and even had it being read again. She was very apologetic - works, kids, life in general. She did finish it the next weekend after sending her kids and husband to her in-laws so there were no distractions. After all of that, most of everything she said had been brought to my attention and dealt with. Yet, her notes were very thorough. I thanked her and she offered to beta for me again in a timely fashion. Which has happened.