So above is a trendline which would be a bearish trendline or down trendline, as you can see it’s drawn kind of inverted like, the yellow circles are where it touches to confirm the trendline and the blue circle is where a entry would be if that candle closes below the trendline, I’d wait for the pull back to the trendline to enter. Is this a valid trendline?
According to me, no; it’s not! Since, the middle portion already had broken the line.
A trend-line should start at a significant high or low (this line starts at the low of a candle three after a significant low). Price should then touch the line twice more and re-bound before you can call it a trend-line. Your line is touched once by the low of a long green bar and two later bars but is broken by the one after and a bar two bars later at which time price even closes below the line. At this time, even if you had adjusted the start point to the significant low, the trend-line was broken and of no further use.
There is a much lower potential bearish trend-line (not marked) and price is currently falling towards this. If it re-bounds upwards that would confirm this line but its not confirmed yet by the second touch so its not useful as reference yet.
No sadly that is not.
A good thing to look at when charting trendlines would be Lower Highs (Down Trend), and Higher Lows (Up Trend).
Connect the first two LHs for a downtrend - and for an uptrend the first two HLs. Hope this helped! 
[Edited for a Forum Violation]