By age of 30 it is not a natural process. Vigorous wrong brushing technique can be one of the causes for gingival recession. By age of 50-55 that can happen. Naturally. Can be seen in diabetic patient with periodontal problem at early age.

Dear practo user This is not natural or aging process.

Its all depends on your oral hygiene,if you maintain oral hygiene,visit dentist for scaling (normal cleaning) on regular intervals,the gums and teeth will remain healthy

In young and early 30's or at mid 40's is not common unless and until the concerned person's brushing behavior whether it vigorous brushing, long spell brushing, not changing the brush at the right time and even using a hard toothbrush can be the reasons and if the person is having diabetes and periodontal problems will be facing those issues.