At 70 is it still possible that I might get skin cancer on my arms and legs and belly exposed by bikini?

Cumulative damage. Skin cancers are caused by cumulative damage to the skin. Generally the more sun you had in the past, the higher the chance of skin cancer. If you spent a lot of time in the sun in a bikini, then those areas which were exposed to the sun will be at risk for skin cancer. If you suspect a skin cancer, get it checked out. The sooner the treatment, the better the chance of cure.
Yes. Skin cancer becomes more common as we age. If you have any spots on your skin that either were not previously there, or are enlarging, you should see a dermatologist.
YES! The type of sun damage that can cause melanoma is cumulative, meaning that your skin doesn't forget the sun exposure from 1 day ago or 30 years ago! Increased age is a risk factor, especially if you have had a history of sun exposure. Use sun screen SPF 50 or greater with frequent reapplications, avoid the sun, and get regular skin exams from your doctor (every 6 months).

Related Questions

Possible that I might get skin cancer on my arms and legs if already on my face?

Yes. If ou have fair skin and significant sun exposure you should have whole body screening including arms, legs, trunk, feet and scalp. Typically basl cell carcinomas are the most common, but if you have one or more kin cancers on your face you should have check up a minimum of once a year.
Yes. Yes, but the relative frequency depends on type of skin cancer and your own skin type and sun exposure. Melanomas can occur anywhere. Squamous and basal cancers are much more likely in sun-exposed areas, like the face, scalp, back of arms, etc. If you have had a skin cancer - you should be checked from time to time by your dermatologist or primary doctor.
Very possible. Skin cancer is due to sun exposure. The head and neck is very common, as are the exposed areas of the arms, hands and legs. If you have any concerning lesions seek evaluation soon. Otherwise, just keep the surveillance appointments your dermatologist has likely scheduled for you.