SPI, RS232 and DMX-512 data signals beneath the ESP8266-WROOM-02 Wifi antenna
Yes, this will affect the RF performance, MIFA type antennas typically need a minimum amount of free space around them to get best performance and they really don't like ground/power planes directly underneath.  It's not as much as one would think, but you also should consider whatever case design you have, etc.  Reference materials are available easiest way to get them is to go either here:
https://www.digikey.com/product-detail/en/espressif-systems/ESP-WROOM-02/1904-1009-1-ND/8544304?utm_adgroup=RF%20&amp;%20RFID
Note the placement design guide and datasheet pdf docs.

Note that your current layout will most likely still transmit/receive a signal that operates over a (perhaps severely) reduced range so you could still find some use if you've already ordered the board design.