So: do you join a women's weight loss group or do it by yourself?
There is no "one size fits all". You are an individual, and you need to do what's best for you. One helpful idea to keep in mind is that whatever way you choose, you can change to something else if it's not working out for you.
Reaching out for help to either a weight loss group, or perhaps a dieting buddy or a nutritional counselor has helped many women. Then, of course, many have successfully found ways to lose weight on their own.