time is a concept used to measure and only needs a beginning to be able to be measured. for example I am writing this post at 3:18pm therefore I can measure the time that has passed from this time. some people may measure time in a different way than I do but it none the less can be measured.
Is God outside of time?
well yes and no. in context of how long has God been He is out of time why?
because it can not be measured, there is no beginning or end to start the measurement. Yet I can however measure the time He has existed from a point in my past, E.G. since 3pm to now which is 3:21 pm God has existed 21 minutes.
time is a made up name for a measurement of well, time
is God inside or outside of time? we don't know because we don't know the context or the truth of time. we have a basic understanding and it doesn't matter anyway.
God is! and that is enough for me.