Best weights to start with for females?

Do you only have one dumbbell? The weight depends on your strength level for each exercise. You don't always lift the same amount of weight for each body part. As you practice, you will be able to increase the amount you lift. Do you have access to more weights?
Have you looked at some YouTube workouts for ideas? These ladies have some great workouts, with and without dumbbells:
Sydney Cummings
Growingannanas
Caroline Girvan

I would suggest a set of adjustable dumbbells might suit you better.

That way you can both adjust for the different requirements for different exercises (for compound lifts 7kg may well be far too light if it's currently suitable for you doing isolation exercises) and also your increasing strength over time.

One thing I would add, would be to get on a structured program lifting/resistance program that you can follow. This will help provide guidance/direction for you. Essentially, simplifies things.


https://community.myfitnesspal.com/en/discussion/10332083/which-lifting-program-is-the-best-for-you/p1

Also, it's not about weight in the beginning but about form. The drawback on working out at home for many is that they get no feedback on whether or not they are executing an exercise correctly. I'd reference an exercise, then do it with no weight in front of a mirror and look from as many angles as I could first.

A.C.E. Certified Personal and Group Fitness Trainer
IDEA Fitness member
Kickboxing Certified Instructor
Been in fitness for 30 years and have studied kinesiology and nutrition