If you want to check how old is some trade, using pink blocks, there is a block "check age" which can be used and it feels more naturally.
If you want to create input parameter for the EA where you can select different timeframes, you can make it with data type ENUM_TIMEFRAMES. As a default value you can have PERIOD_M15, which is a predefind constant. Here is more info: https://www.mql5.com/en/docs/constants/chartconstants/enum_timeframes