Like people have said, talk to your doctor, but it seems to me like it’s not something you should be waiting too long for

Study regarding vitamin D levels

There is a significant positive correlation between afternoon sunlight exposure and infant's vitamin D levels, independent of maternal vitamin D status.

Study claiming exposure, or at least vitamin D supplementation, decreases chance of developIng allergic disorders

Four meteorological exposure trajectories were found. The trajectory with the highest exposure to early solar radiation had a reduced risk of sensitization at 8-9 years compared to the trajectory with the lowest exposure

Small study claiming vitamin D supplementation alone might be fine

Oral vitamin D3 supplementation is more efficacious than sunlight in achieving vitamin D sufficiency in breastfed infants during the first 6 months of life due to better compliance.

You may want to consider supplementing D3 if you aren’t already

Although the vitamin is synthesized in the skin with the help of sunlight, it is mostly agreed by various groups that oral supplementation must be done in infants and in certain high risk groups.