what's a non-standard transaction?
could a fee be too low if I kept the default fee, using a good wallet? Or would it only happen if I lowered the fee myself?
Non-standard transactions are transactions that are not relayed by the nodes but are otherwise perfectly valid and are able to be mined. An example would be a transaction having 10 satoshis as one of it's output. It is a non-standard transaction as that is defined as dust. Another example would be sending a transaction without fees, etc.
Each wallet has their own individual fee estimation and it is impossible to ascertain the accuracy of it. Sudden spikes in transaction volumes are unpredictable and could result in your transaction taking way longer to confirm. More often than not, they are fairly accurate.
What fee did you pay?
1Satoshi/Byte
don't rememeber which transaction was it, it was either 1980sats for a 1262500sats transfer, or a 3936 fee for a 9900000 transaction..one or the other, using edge wallet.
is edge a recommended wallet, or is it just good for noobs?
The transaction fee is independent of the amount of Bitcoins transferred. It is directly affected by the size of the transaction instead.
I have never used Edge wallet. I use Electrum personally and I find it suitable for my use.