Peer assessment is a great idea. It means you can get students to really work with the rubric, and in the process learn to self-assess and reflect on their own learning, those super-valuable metacognitive habits of mind.

BUT it can be a logistical problem. 25 class members multiplied by 25 assessments, with say 5 criteria to assess. That's 3125 items of data! What are you going to do with that? Well, you can start by using a Google Form to collect the data, and then analyse the data with a pivot table. Here are the steps to follow:

1. Create your form based on your rubric. Keep it simple and short, while still retaining the main skills which you would like students to really think about.
2. Include a question: who is being assessed? Pre-populate this with a list of students in your class. TIP: you can copy a list off a spreadsheet and paste it.
3. Include a question: who is doing the assessment? Provide the options: A classmate, Myself, The teacher
4. Include a glows (positives) and grows (suggestions for improvement) open-ended text question.
5. Whan all the assessments are complete, open the spreadsheet where the responses are recorded.
6. Select Data > Pivot Table from the menu. Create a new sheet.
7. Under Rows, select: who is being assessed and who is doing the assessment.
8. Under values select each of your rubric criteria and set them as follows: Values as Columns; Summarise by Average.
9. This should give you 3 scores for each student for each criterion. It is interesting and useful to compare them. Does the student undervalue or overvalue herself in relation to you and/or the peers? This can lead to a useful discussion.
10. To get a single score for each, close up the student by clicking the minus.
11. The way I use the scores is to add them to a rubric for a bigger project/assignment in Google Classroom. Eg if this peer assessment is for a presentation, I score the technical aspects of the presentation in a rubric and then add the peer assessment criteria to the same rubric. 
12. The way I use the glows & grows is to copy all the relevant cells from the main spreadsheet and paste them into the comments section of the assessment screen in GC.