No danger, most tinctures will attain maximum potency (it varies a bit from herb to herb) in under two months, providing they are shaken/stirred daily. With more time, the need for shaking is lessened. After the initial maceration period, the menstruum will take no more of the herbs active constituents, an equilibrium is reached, and the strength does not continue to increase with time.
Most tinctures retain decent potency for about 18 months/2 years. After that, the potency begins to diminish at a higher rate. Same story for most dried herbs.
I think your medicines are still very good, providing they were kept in the dark and not exposed to excessive heat.
Continue your medicine making, proceed with confidence, I'd bet you have a good year or more of potency left.
desire nothing. be content with everything.